xref: /freebsd/contrib/tzdata/NEWS (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1News for the tz database
2
3Release 2024b - 2024-09-04 12:27:47 -0700
4
5  Briefly:
6    Improve historical data for Mexico, Mongolia, and Portugal.
7    System V names are now obsolescent.
8    The main data form now uses %z.
9    The code now conforms to RFC 8536 for early timestamps.
10    Support POSIX.1-2024, which removes asctime_r and ctime_r.
11    Assume POSIX.2-1992 or later for shell scripts.
12    SUPPORT_C89 now defaults to 1.
13
14  Changes to past timestamps
15
16    Asia/Choibalsan is now an alias for Asia/Ulaanbaatar rather than
17    being a separate Zone with differing behavior before April 2008.
18    This seems better given our wildly conflicting information about
19    Mongolia's time zone history.  (Thanks to Heitor David Pinto.)
20
21    Historical transitions for Mexico have been updated based on
22    official Mexican decrees.  The affected timestamps occur during
23    the years 1921-1927, 1931, 1945, 1949-1970, and 1981-1997.
24    The affected zones are America/Bahia_Banderas, America/Cancun,
25    America/Chihuahua, America/Ciudad_Juarez, America/Hermosillo,
26    America/Mazatlan, America/Merida, America/Mexico_City,
27    America/Monterrey, America/Ojinaga, and America/Tijuana.
28    (Thanks to Heitor David Pinto.)
29
30    Historical transitions for Portugal, represented by Europe/Lisbon,
31    Atlantic/Azores, and Atlantic/Madeira, have been updated based on a
32    close reading of old Portuguese legislation, replacing previous data
33    mainly originating from Whitman and Shanks & Pottenger.  These
34    changes affect a few transitions in 1917-1921, 1924, and 1940
35    throughout these regions by a few hours or days, and various
36    timestamps between 1977 and 1993 depending on the region.  In
37    particular, the Azores and Madeira did not observe DST from 1977 to
38    1981.  Additionally, the adoption of standard zonal time in former
39    Portuguese colonies have been adjusted: Africa/Maputo in 1909, and
40    Asia/Dili by 22 minutes at the start of 1912.
41    (Thanks to Tim Parenti.)
42
43  Changes to past tm_isdst flags
44
45    The period from 1966-04-03 through 1966-10-02 in Portugal is now
46    modeled as DST, to more closely reflect how contemporaneous changes
47    in law entered into force.
48
49  Changes to data
50
51    Names present only for compatibility with UNIX System V
52    (last released in the 1990s) have been moved to 'backward'.
53    These names, which for post-1970 timestamps mostly just duplicate
54    data of geographical names, were confusing downstream uses.
55    Names moved to 'backward' are now links to geographical names.
56    This affects behavior for TZ='EET' for some pre-1981 timestamps,
57    for TZ='CET' for some pre-1947 timestamps, and for TZ='WET' for
58    some pre-1996 timestamps.  Also, TZ='MET' now behaves like
59    TZ='CET' and so uses the abbreviation "CET" rather than "MET".
60    Those needing the previous TZDB behavior, which does not match any
61    real-world clocks, can find the old entries in 'backzone'.
62    (Problem reported by Justin Grant.)
63
64    The main source files' time zone abbreviations now use %z,
65    supported by zic since release 2015f and used in vanguard form
66    since release 2022b.  For example, America/Sao_Paulo now contains
67    the zone continuation line "-3:00 Brazil %z", which is less error
68    prone than the old "-3:00 Brazil -03/-02".  This does not change
69    the represented data: the generated TZif files are unchanged.
70    Rearguard form still avoids %z, to support obsolescent parsers.
71
72    Asia/Almaty has been removed from zonenow.tab as it now agrees
73    with Asia/Tashkent for future timestamps, due to Kazakhstan's
74    2024-02-29 time zone change.  Similarly, America/Scoresbysund
75    has been removed, as it now agrees with America/Nuuk due to
76    its 2024-03-31 time zone change.
77
78  Changes to code
79
80    localtime.c now always uses a TZif file's time type 0 to handle
81    timestamps before the file's first transition.  Formerly,
82    localtime.c sometimes inferred a different time type, in order to
83    handle problematic data generated by zic 2018e or earlier.  As it
84    is now safe to assume more recent versions of zic, there is no
85    longer a pressing need to fail to conform RFC 8536 section 3.2,
86    which requires using time type 0 in this situation.  This change
87    does not affect behavior when reading TZif files generated by zic
88    2018f and later.
89
90    POSIX.1-2024 removes asctime_r and ctime_r and does not let
91    libraries define them, so remove them except when needed to
92    conform to earlier POSIX.  These functions are dangerous as they
93    can overrun user buffers.  If you still need them, add
94    -DSUPPORT_POSIX2008 to CFLAGS.
95
96    The SUPPORT_C89 option now defaults to 1 instead of 0, fixing a
97    POSIX-conformance bug introduced in 2023a.
98
99    tzselect now supports POSIX.1-2024 proleptic TZ strings.  Also, it
100    assumes POSIX.2-1992 or later, as practical porting targets now
101    all support that, and it uses some features from POSIX.1-2024 if
102    available.
103
104  Changes to build procedure
105
106    'make check' no longer requires curl and Internet access.
107
108    The build procedure now assumes POSIX.2-1992 or later, to simplify
109    maintenance.  To build on Solaris 10, the only extant system still
110    defaulting to pre-POSIX, prepend /usr/xpg4/bin to PATH.
111
112  Changes to documentation
113
114    The documentation now reflects POSIX.1-2024.
115
116  Changes to commentary
117
118    Commentary about historical transitions in Portugal and her former
119    colonies has been expanded with links to many relevant legislation.
120    (Thanks to Tim Parenti.)
121
122
123Release 2024a - 2024-02-01 09:28:56 -0800
124
125  Briefly:
126    Kazakhstan unifies on UTC+5 beginning 2024-03-01.
127    Palestine springs forward a week later after Ramadan.
128    zic no longer pretends to support indefinite-past DST.
129    localtime no longer mishandles Ciudad Juárez in 2422.
130
131  Changes to future timestamps
132
133    Kazakhstan unifies on UTC+5.  This affects Asia/Almaty and
134    Asia/Qostanay which together represent the eastern portion of the
135    country that will transition from UTC+6 on 2024-03-01 at 00:00 to
136    join the western portion.  (Thanks to Zhanbolat Raimbekov.)
137
138    Palestine springs forward a week later than previously predicted
139    in 2024 and 2025.  (Thanks to Heba Hamad.)  Change spring-forward
140    predictions to the second Saturday after Ramadan, not the first;
141    this also affects other predictions starting in 2039.
142
143  Changes to past timestamps
144
145    Asia/Ho_Chi_Minh's 1955-07-01 transition occurred at 01:00
146    not 00:00.  (Thanks to Đoàn Trần Công Danh.)
147
148    From 1947 through 1949, Toronto's transitions occurred at 02:00
149    not 00:00.  (Thanks to Chris Walton.)
150
151    In 1911 Miquelon adopted standard time on June 15, not May 15.
152
153  Changes to code
154
155    The FROM and TO columns of Rule lines can no longer be "minimum"
156    or an abbreviation of "minimum", because TZif files do not support
157    DST rules that extend into the indefinite past - although these
158    rules were supported when TZif files had only 32-bit data, this
159    stopped working when 64-bit TZif files were introduced in 1995.
160    This should not be a problem for realistic data, since DST was
161    first used in the 20th century.  As a transition aid, FROM columns
162    like "minimum" are now diagnosed and then treated as if they were
163    the year 1900; this should suffice for TZif files on old systems
164    with only 32-bit time_t, and it is more compatible with bugs in
165    2023c-and-earlier localtime.c.  (Problem reported by Yoshito
166    Umaoka.)
167
168    localtime and related functions no longer mishandle some
169    timestamps that occur about 400 years after a switch to a time
170    zone with a DST schedule.  In 2023d data this problem was visible
171    for some timestamps in November 2422, November 2822, etc. in
172    America/Ciudad_Juarez.  (Problem reported by Gilmore Davidson.)
173
174    strftime %s now uses tm_gmtoff if available.  (Problem and draft
175    patch reported by Dag-Erling Smørgrav.)
176
177  Changes to build procedure
178
179    The leap-seconds.list file is now copied from the IERS instead of
180    from its downstream counterpart at NIST, as the IERS version is
181    now in the public domain too and tends to be more up-to-date.
182    (Thanks to Martin Burnicki for liaisoning with the IERS.)
183
184  Changes to documentation
185
186    The strftime man page documents which struct tm members affect
187    which conversion specs, and that tzset is called.  (Problems
188    reported by Robert Elz and Steve Summit.)
189
190
191Release 2023d - 2023-12-21 20:02:24 -0800
192
193  Briefly:
194    Ittoqqortoormiit, Greenland changes time zones on 2024-03-31.
195    Vostok, Antarctica changed time zones on 2023-12-18.
196    Casey, Antarctica changed time zones five times since 2020.
197    Code and data fixes for Palestine timestamps starting in 2072.
198    A new data file zonenow.tab for timestamps starting now.
199
200  Changes to future timestamps
201
202    Ittoqqortoormiit, Greenland (America/Scoresbysund) joins most of
203    the rest of Greenland's timekeeping practice on 2024-03-31, by
204    changing its time zone from -01/+00 to -02/-01 at the same moment
205    as the spring-forward transition.  Its clocks will therefore not
206    spring forward as previously scheduled.  The time zone change
207    reverts to its common practice before 1981.
208
209    Fix predictions for DST transitions in Palestine in 2072-2075,
210    correcting a typo introduced in 2023a.
211
212  Changes to past and future timestamps
213
214    Vostok, Antarctica changed to +05 on 2023-12-18.  It had been at
215    +07 (not +06) for years.  (Thanks to Zakhary V. Akulov.)
216
217    Change data for Casey, Antarctica to agree with timeanddate.com,
218    by adding five time zone changes since 2020.  Casey is now at +08
219    instead of +11.
220
221  Changes to past tm_isdst flags
222
223    Much of Greenland, represented by America/Nuuk, changed its
224    standard time from -03 to -02 on 2023-03-25, not on 2023-10-28.
225    This does not affect UTC offsets, only the tm_isdst flag.
226    (Thanks to Thomas M. Steenholdt.)
227
228  New data file
229
230    A new data file zonenow.tab helps configure applications that use
231    timestamps dated from now on.  This simplifies configuration,
232    since users choose from a smaller Zone set.  The file's format is
233    experimental and subject to change.
234
235  Changes to code
236
237    localtime.c no longer mishandles TZif files that contain a single
238    transition into a DST regime.  Previously, it incorrectly assumed
239    DST was in effect before the transition too.  (Thanks to Alois
240    Treindl for debugging help.)
241
242    localtime.c's timeoff no longer collides with OpenBSD 7.4.
243
244    The C code now uses _Generic only if __STDC_VERSION__ says the
245    compiler is C11 or later.
246
247    tzselect now optionally reads zonenow.tab, to simplify when
248    configuring only for timestamps dated from now on.
249
250    tzselect no longer creates temporary files.
251
252    tzselect no longer mishandles the following:
253
254      Spaces and most other special characters in BUGEMAIL, PACKAGE,
255      TZDIR, and VERSION.
256
257      TZ strings when using mawk 1.4.3, which mishandles regular
258      expressions of the form /X{2,}/.
259
260      ISO 6709 coordinates when using an awk that lacks the GNU
261      extension of newlines in -v option-arguments.
262
263      Non UTF-8 locales when using an iconv command that lacks the GNU
264      //TRANSLIT extension.
265
266    zic no longer mishandles data for Palestine after the year 2075.
267    Previously, it incorrectly omitted post-2075 transitions that are
268    predicted for just before and just after Ramadan.  (Thanks to Ken
269    Murchison for debugging help.)
270
271    zic now works again on Linux 2.6.16 and 2.6.17 (2006).
272    (Problem reported by Rune Torgersen.)
273
274  Changes to build procedure
275
276    The Makefile is now more compatible with POSIX:
277     * It no longer defines AR, CC, CFLAGS, LDFLAGS, and SHELL.
278     * It no longer uses its own 'cc' in place of CC.
279     * It now uses ARFLAGS, with default specified by POSIX.
280     * It does not use LFLAGS incompatibly with POSIX.
281     * It uses the special .POSIX target.
282     * It quotes special characters more carefully.
283     * It no longer mishandles builds in an ISO 8859 locale.
284    Due to the CC changes, TZDIR is now #defined in a file tzdir.h
285    built by 'make', not in a $(CC) -D option.  Also, TZDEFAULT is
286    now treated like TZDIR as they have similar roles.
287
288  Changes to commentary
289
290     Limitations and hazards of the optional support for obsolescent
291     C89 platforms are documented better, along with a tentative
292     schedule for removing this support.
293
294
295Release 2023c - 2023-03-28 12:42:14 -0700
296
297  Changes to past and future timestamps
298
299    Model Lebanon's DST chaos by reverting data to tzdb 2023a.
300    (Thanks to Rany Hany for the heads-up.)
301
302
303Release 2023b - 2023-03-23 19:50:38 -0700
304
305  Changes to future timestamps
306
307    This year Lebanon springs forward April 20/21 not March 25/26.
308    (Thanks to Saadallah Itani.)  [This was reverted in 2023c.]
309
310
311Release 2023a - 2023-03-22 12:39:33 -0700
312
313  Briefly:
314    Egypt now uses DST again, from April through October.
315    This year Morocco springs forward April 23, not April 30.
316    Palestine delays the start of DST this year.
317    Much of Greenland still uses DST from 2024 on.
318    America/Yellowknife now links to America/Edmonton.
319    tzselect can now use current time to help infer timezone.
320    The code now defaults to C99 or later.
321    Fix use of C23 attributes.
322
323  Changes to future timestamps
324
325    Starting in 2023, Egypt will observe DST from April's last Friday
326    through October's last Thursday.  (Thanks to Ahmad ElDardiry.)
327    Assume the transition times are 00:00 and 24:00, respectively.
328
329    In 2023 Morocco's spring-forward transition after Ramadan
330    will occur April 23, not April 30.  (Thanks to Milamber.)
331    Adjust predictions for future years accordingly.  This affects
332    predictions for 2023, 2031, 2038, and later years.
333
334    This year Palestine will delay its spring forward from
335    March 25 to April 29 due to Ramadan.  (Thanks to Heba Hamad.)
336    Make guesses for future Ramadans too.
337
338    Much of Greenland, represented by America/Nuuk, will continue to
339    observe DST using European Union rules.  When combined with
340    Greenland's decision not to change the clocks in fall 2023,
341    America/Nuuk therefore changes from -03/-02 to -02/-01 effective
342    2023-10-29 at 01:00 UTC.  (Thanks to Thomas M. Steenholdt.)
343    This change from 2022g doesn't affect timestamps until 2024-03-30,
344    and doesn't affect tm_isdst until 2023-03-25.
345
346  Changes to past timestamps
347
348    America/Yellowknife has changed from a Zone to a backward
349    compatibility Link, as it no longer differs from America/Edmonton
350    since 1970.  (Thanks to Almaz Mingaleev.)  This affects some
351    pre-1948 timestamps.  The old data are now in 'backzone'.
352
353  Changes to past time zone abbreviations
354
355    When observing Moscow time, Europe/Kirov and Europe/Volgograd now
356    use the abbreviations MSK/MSD instead of numeric abbreviations,
357    for consistency with other timezones observing Moscow time.
358
359  Changes to code
360
361    You can now tell tzselect local time, to simplify later choices.
362    Select the 'time' option in its first prompt.
363
364    You can now compile with -DTZNAME_MAXIMUM=N to limit time zone
365    abbreviations to N bytes (default 255).  The reference runtime
366    library now rejects POSIX-style TZ strings that contain longer
367    abbreviations, treating them as UTC.  Previously the limit was
368    platform dependent and abbreviations were silently truncated to
369    16 bytes even when the limit was greater than 16.
370
371    The code by default is now designed for C99 or later.  To build on
372    a mostly-C89 platform, compile with -DPORT_TO_C89; this should
373    work on C89 platforms that also support C99 'long long' and
374    perhaps a few other extensions to C89.  To support C89 callers of
375    tzcode's library, compile with -DSUPPORT_C89; however, this could
376    trigger latent bugs in C99-or-later callers.  The two new macros
377    are transitional aids planned to be removed in a future version
378    (say, in 2029), when C99 or later will be required.
379
380    The code now builds again on pre-C99 platforms, if you compile
381    with -DPORT_TO_C89.  This fixes a bug introduced in 2022f.
382
383    On C23-compatible platforms tzcode no longer uses syntax like
384    'static [[noreturn]] void usage(void);'.  Instead, it uses
385    '[[noreturn]] static void usage(void);' as strict C23 requires.
386    (Problem reported by Houge Langley.)
387
388    The code's functions now constrain their arguments with the C
389    'restrict' keyword consistently with their documentation.
390    This may allow future optimizations.
391
392    zdump again builds standalone with ckdadd and without setenv,
393    fixing a bug introduced in 2022g.  (Problem reported by panic.)
394
395    leapseconds.awk can now process a leap seconds file that never
396    expires; this might be useful if leap seconds are discontinued.
397
398  Changes to commentary
399
400    tz-link.html has a new section "Coordinating with governments and
401    distributors".  (Thanks to Neil Fuller for some of the text.)
402
403    To improve tzselect diagnostics, zone1970.tab's comments column is
404    now limited to countries that have multiple timezones.
405
406    Note that there are plans to discontinue leap seconds by 2035.
407
408
409Release 2022g - 2022-11-29 08:58:31 -0800
410
411  Briefly:
412    The northern edge of Chihuahua changes to US timekeeping.
413    Much of Greenland stops changing clocks after March 2023.
414    Fix some pre-1996 timestamps in northern Canada.
415    C89 is now deprecated; please use C99 or later.
416    Portability fixes for AIX, libintl, MS-Windows, musl, z/OS
417    In C code, use more C23 features if available.
418    C23 timegm now supported by default
419    Fixes for unlikely integer overflows
420
421  Changes to future timestamps
422
423    In the Mexican state of Chihuahua, the border strip near the US
424    will change to agree with nearby US locations on 2022-11-30.
425    The strip's western part, represented by Ciudad Juárez, switches
426    from -06 all year to -07/-06 with US DST rules, like El Paso, TX.
427    The eastern part, represented by Ojinaga, will observe US DST next
428    year, like Presidio, TX.  (Thanks to Heitor David Pinto.)
429    A new Zone America/Ciudad_Juarez splits from America/Ojinaga.
430
431    Much of Greenland, represented by America/Nuuk, stops observing
432    winter time after March 2023, so its daylight saving time becomes
433    standard time.  (Thanks to Jonas Nyrup and Jürgen Appel.)
434
435  Changes to past timestamps
436
437    Changes for pre-1996 northern Canada (thanks to Chris Walton):
438
439      Merge America/Iqaluit and America/Pangnirtung into the former,
440      with a backward compatibility link for the latter name.
441      There is no good evidence the two locations differ since 1970.
442      This change affects pre-1996 America/Pangnirtung timestamps.
443
444      Cambridge Bay, Inuvik, Iqaluit, Rankin Inlet, Resolute and
445      Yellowknife did not observe DST in 1965, and did observe DST
446      from 1972 through 1979.
447
448      Whitehorse moved from -09 to -08 on 1966-02-27, not 1967-05-28.
449
450    Colombia's 1993 fallback was 02-06 24:00, not 04-04 00:00.
451    (Thanks to Alois Treindl.)
452
453    Singapore's 1981-12-31 change was at 16:00 UTC (23:30 local time),
454    not 24:00 local time.  (Thanks to Geoff Clare via Robert Elz.)
455
456  Changes to code
457
458    Although tzcode still works with C89, bugs found in recent routine
459    maintenance indicate that bitrot has set in and that in practice
460    C89 is no longer used to build tzcode.  As it is a maintenance
461    burden, support for C89 is planned to be removed soon.  Instead,
462    please use compilers compatible with C99, C11, C17, or C23.
463
464    timegm, which tzcode implemented in 1989, will finally be
465    standardized 34 years later as part of C23, so timegm is now
466    supported even if STD_INSPIRED is not defined.
467
468    Fix bug in zdump's tzalloc emulation on hosts that lack tm_zone.
469    (Problem reported by Đoàn Trần Công Danh.)
470
471    Fix bug in zic on hosts where malloc(0) yields NULL on success.
472    (Problem reported by Tim McBrayer for AIX 6.1.)
473
474    Fix zic configuration to avoid linkage failures on some platforms.
475    (Problems reported by Gilmore Davidson and Igor Ivanov.)
476
477    Work around MS-Windows nmake incompatibility with POSIX.
478    (Problem reported by Manuela Friedrich.)
479
480    Port mktime and strftime to debugging platforms where accessing
481    uninitialized data has undefined behavior (strftime problem
482    reported by Robert Elz).
483
484    Check more carefully for unlikely integer overflows, preferring
485    C23 <stdckdint.h> to overflow checking by hand, as the latter has
486    had obscure bugs.
487
488  Changes to build procedure
489
490    New Makefile rule check_mild that skips checking whether Link
491    lines are in the file 'backward'.  (Inspired by a suggestion from
492    Stephen Colebourne.)
493
494
495Release 2022f - 2022-10-28 18:04:57 -0700
496
497  Briefly:
498    Mexico will no longer observe DST except near the US border.
499    Chihuahua moves to year-round -06 on 2022-10-30.
500    Fiji no longer observes DST.
501    Move links to 'backward'.
502    In vanguard form, GMT is now a Zone and Etc/GMT a link.
503    zic now supports links to links, and vanguard form uses this.
504    Simplify four Ontario zones.
505    Fix a Y2438 bug when reading TZif data.
506    Enable 64-bit time_t on 32-bit glibc platforms.
507    Omit large-file support when no longer needed.
508    In C code, use some C23 features if available.
509    Remove no-longer-needed workaround for Qt bug 53071.
510
511  Changes to future timestamps
512
513    Mexico will no longer observe DST after 2022, except for areas
514    near the US border that continue to observe US DST rules.
515    On 2022-10-30 at 02:00 the Mexican state of Chihuahua moves
516    from -07 (-06 with DST) to year-round -06, thus not changing
517    its clocks that day.  The new law states that Chihuahua
518    near the US border no longer observes US DST.
519    (Thanks to gera for the heads-up about Chihuahua.)
520
521    Fiji will not observe DST in 2022/3.  (Thanks to Shalvin Narayan.)
522    For now, assume DST is suspended indefinitely.
523
524  Changes to data
525
526    Move links to 'backward' to ease and simplify link maintenance.
527    This affects generated data only if you use 'make BACKWARD='.
528
529    GMT is now a Zone and Etc/GMT a link instead of vice versa,
530    as GMT is needed for leap second support whereas Etc/GMT is not.
531    However, this change exposes a bug in TZUpdater 2.3.2 so it is
532    present only in vanguard form for now.
533
534    Vanguard form now uses links to links, as zic now supports this.
535
536  Changes to past timestamps
537
538    Simplify four Ontario zones, as most of the post-1970 differences
539    seem to have been imaginary.  (Problem reported by Chris Walton.)
540    Move America/Nipigon, America/Rainy_River, and America/Thunder_Bay
541    to 'backzone'; backward-compatibility links still work, albeit
542    with some different timestamps before November 2005.
543
544  Changes to code
545
546    zic now supports links to links regardless of input line order.
547    For example, if Australia/Sydney is a Zone, the lines
548      Link Australia/Canberra Australia/ACT
549      Link Australia/Sydney Australia/Canberra
550    now work correctly, even though the shell commands
551      ln Australia/Canberra Australia/ACT
552      ln Australia/Sydney Australia/Canberra
553    would fail because the first command attempts to use a link
554    Australia/Canberra that does not exist until after the second
555    command is executed.  Previously, zic had unspecified behavior if
556    a Link line's target was another link, and zic often misbehaved if
557    a Link line's target was a later Link line.
558
559    Fix line number in zic's diagnostic for a link to a link.
560
561    Fix a bug that caused localtime to mishandle timestamps starting
562    in the year 2438 when reading data generated by 'zic -b fat' when
563    distant-future DST transitions occur at times given in standard
564    time or in UT, not the usual case of local time.  This occurs when
565    the corresponding .zi Rule lines specify DST transitions with TO
566    columns of 'max' and AT columns that end in 's' or 'u'.  The
567    number 2438 comes from the 32-bit limit in the year 2038, plus the
568    400-year Gregorian cycle.  (Problem reported by Bradley White.)
569
570    On glibc 2.34 and later, which optionally supports 64-bit time_t
571    on platforms like x86 where time_t was traditionally 32 bits,
572    default time_t to 64 instead of 32 bits.  This lets functions like
573    localtime support timestamps after the year 2038, and fixes
574    year-2038 problems in zic when accessing files dated after 2038.
575    To continue to limit time_t to 32 bits on these platforms, use
576    "make CFLAGS='-D_TIME_BITS=32'".
577
578    In C code, do not enable large-file support on platforms like AIX
579    and macOS that no longer need it now that tzcode does not use
580    off_t or related functions like 'stat'.  Large-file support is
581    still enabled by default on GNU/Linux, as it is needed for 64-bit
582    time_t support.
583
584    In C code, prefer C23 keywords to pre-C23 macros for alignof,
585    bool, false, and true.  Also, use the following C23 features if
586    available: __has_include, unreachable.
587
588    zic no longer works around Qt bug 53071, as the relevant Qt
589    releases have been out of support since 2019.  This change affects
590    only fat TZif files, as thin files never had the workaround.
591
592    zdump no longer modifies the environ vector when compiled on
593    platforms lacking tm_zone or when compiled with -DUSE_LTZ=0.
594    This avoid undefined behavior on POSIX platforms.
595
596
597Release 2022e - 2022-10-11 11:13:02 -0700
598
599  Briefly:
600    Jordan and Syria switch from +02/+03 with DST to year-round +03.
601
602  Changes to future timestamps
603
604    Jordan and Syria are abandoning the DST regime and are changing to
605    permanent +03, so they will not fall back from +03 to +02 on
606    2022-10-28.  (Thanks to Steffen Thorsen and Issam Al-Zuwairi.)
607
608  Changes to past timestamps
609
610    On 1922-01-01 Tijuana adopted standard time at 00:00, not 01:00.
611
612  Changes to past time zone abbreviations and DST flags
613
614    The temporary advancement of clocks in central Mexico in summer
615    1931 is now treated as daylight saving time, instead of as two
616    changes to standard time.
617
618
619Release 2022d - 2022-09-23 12:02:57 -0700
620
621  Briefly:
622    Palestine transitions are now Saturdays at 02:00.
623    Simplify three Ukraine zones into one.
624
625  Changes to future timestamps
626
627    Palestine now springs forward and falls back at 02:00 on the
628    first Saturday on or after March 24 and October 24, respectively.
629    This means 2022 falls back 10-29 at 02:00, not 10-28 at 01:00.
630    (Thanks to Heba Hamad.)
631
632  Changes to past timestamps
633
634    Simplify three Ukraine zones to one, since the post-1970
635    differences seem to have been imaginary.  Move Europe/Uzhgorod and
636    Europe/Zaporozhye to 'backzone'; backward-compatibility links
637    still work, albeit with different timestamps before October 1991.
638
639
640Release 2022c - 2022-08-15 17:47:18 -0700
641
642  Briefly:
643    Work around awk bug in FreeBSD, macOS, etc.
644    Improve tzselect on intercontinental Zones.
645
646  Changes to code
647
648    Work around a bug in onetrueawk that broke commands like
649    'make traditional_tarballs' on FreeBSD, macOS, etc.
650    (Problem reported by Deborah Goldsmith.)
651
652    Add code to tzselect that uses experimental structured comments in
653    zone1970.tab to clarify whether Zones like Africa/Abidjan and
654    Europe/Istanbul cross continent or ocean boundaries.
655    (Inspired by a problem reported by Peter Krefting.)
656
657    Fix bug with 'zic -d /a/b/c' when /a is unwritable but the
658    directory /a/b already exists.
659
660    Remove zoneinfo2tdf.pl, as it was unused and triggered false
661    malware alarms on some email servers.
662
663
664Release 2022b - 2022-08-10 15:38:32 -0700
665
666  Briefly:
667    Chile's DST is delayed by a week in September 2022.
668    Iran no longer observes DST after 2022.
669    Rename Europe/Kiev to Europe/Kyiv.
670    New zic -R option
671    Vanguard form now uses %z.
672    Finish moving duplicate-since-1970 zones to 'backzone'.
673    New build option PACKRATLIST
674    New tailored_tarballs target, replacing rearguard_tarballs
675
676  Changes to future timestamps
677
678    Chile's 2022 DST start is delayed from September 4 to September 11.
679    (Thanks to Juan Correa.)
680
681    Iran plans to stop observing DST permanently, after it falls back
682    on 2022-09-21.  (Thanks to Ali Mirjamali.)
683
684  Changes to past timestamps
685
686    Finish moving to 'backzone' the location-based zones whose
687    timestamps since 1970 are duplicates; adjust links accordingly.
688    This change ordinarily affects only pre-1970 timestamps, and with
689    the new PACKRATLIST option it does not affect any timestamps.
690    In this round the affected zones are Antarctica/Vostok,
691    Asia/Brunei, Asia/Kuala_Lumpur, Atlantic/Reykjavik,
692    Europe/Amsterdam, Europe/Copenhagen, Europe/Luxembourg,
693    Europe/Monaco, Europe/Oslo, Europe/Stockholm, Indian/Christmas,
694    Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Reunion,
695    Pacific/Chuuk, Pacific/Funafuti, Pacific/Majuro, Pacific/Pohnpei,
696    Pacific/Wake and Pacific/Wallis, and the affected links are
697    Arctic/Longyearbyen, Atlantic/Jan_Mayen, Iceland, Pacific/Ponape,
698    Pacific/Truk, and Pacific/Yap.
699
700    From fall 1994 through fall 1995, Shanks wrote that Crimea's
701    DST transitions were at 02:00 standard time, not at 00:00.
702    (Thanks to Michael Deckers.)
703
704    Iran adopted standard time in 1935, not 1946.  In 1977 it observed
705    DST from 03-21 23:00 to 10-20 24:00; its 1978 transitions were on
706    03-24 and 08-05, not 03-20 and 10-20; and its spring 1979
707    transition was on 05-27, not 03-21.
708    (Thanks to Roozbeh Pournader and Francis Santoni.)
709
710    Chile's observance of -04 from 1946-08-29 through 1947-03-31 was
711    considered DST, not standard time.  Santiago and environs had moved
712    their clocks back to rejoin the rest of mainland Chile; put this
713    change at the end of 1946-08-28.  (Thanks to Michael Deckers.)
714
715    Some old, small clock transitions have been removed, as people at
716    the time did not change their clocks.  This affects Asia/Hong_Kong
717    in 1904, Asia/Ho_Chi_Minh in 1906, and Europe/Dublin in 1880.
718
719  Changes to zone name
720
721    Rename Europe/Kiev to Europe/Kyiv, as "Kyiv" is more common in
722    English now.  Spelling of other names in Ukraine has not yet
723    demonstrably changed in common English practice so for now these
724    names retain old spellings, as in other countries (e.g.,
725    Europe/Prague not "Praha", and Europe/Sofia not "Sofiya").
726
727  Changes to code
728
729    zic has a new option '-R @N' to output explicit transitions < N.
730    (Need suggested by Almaz Mingaleev.)
731
732    'zic -r @N' no longer outputs bad data when N < first transition.
733    (Problem introduced in 2021d and reported by Peter Krefting.)
734
735    zic now checks its input for NUL bytes and unterminated lines, and
736    now supports input line lengths up to 2048 (not 512) bytes.
737
738    gmtime and related code now use the abbreviation "UTC" not "GMT".
739    POSIX is being revised to require this.
740
741    When tzset and related functions set vestigial static variables
742    like tzname, they now prefer specified timestamps to unspecified ones.
743    (Problem reported by Almaz Mingaleev.)
744
745    zic no longer complains "can't determine time zone abbreviation to
746    use just after until time" when a transition to a new standard
747    time occurs simultaneously with the first DST fallback transition.
748
749  Changes to build procedure
750
751    Source data in vanguard form now uses the %z notation, introduced
752    in release 2015f.  For example, for America/Sao_Paulo vanguard
753    form contains the zone continuation line "-3:00 Brazil %z", which
754    is simpler and more reliable than the line "-3:00 Brazil -03/-02"
755    used in main and rearguard forms.  The plan is for the main form
756    to use %z eventually; in the meantime maintainers of zi parsers
757    are encouraged to test the parsers on vanguard.zi.
758
759    The Makefile has a new PACKRATLIST option to select a subset of
760    'backzone'.  For example, 'make PACKRATDATA=backzone
761    PACKRATLIST=zone.tab' now generates TZif files identical to those
762    of the global-tz project.
763
764    The Makefile has a new tailored_tarballs target for generating
765    special-purpose tarballs.  It generalizes and replaces the
766    rearguard_tarballs target and related targets and macros, which
767    are now obsolescent.
768
769    'make install' now defaults LOCALTIME to Factory not GMT,
770    which means the default abbreviation is now "-00" not "GMT".
771
772    Remove the posix_packrat target, marked obsolescent in 2016a.
773
774
775Release 2022a - 2022-03-15 23:02:01 -0700
776
777  Briefly:
778    Palestine will spring forward on 2022-03-27, not -03-26.
779    zdump -v now outputs better failure indications.
780    Bug fixes for code that reads corrupted TZif data.
781
782  Changes to future timestamps
783
784    Palestine will spring forward on 2022-03-27, not 2022-03-26.
785    (Thanks to Heba Hamad.)  Predict future transitions for first
786    Sunday >= March 25.  Additionally, predict fallbacks to be the first
787    Friday on or after October 23, not October's last Friday, to be more
788    consistent with recent practice.  The first differing fallback
789    prediction is on 2025-10-24, not 2025-10-31.
790
791  Changes to past timestamps
792
793    From 1992 through spring 1996, Ukraine's DST transitions were at
794    02:00 standard time, not at 01:00 UTC.  (Thanks to Alois Treindl.)
795
796    Chile's Santiago Mean Time and its LMT precursor have been adjusted
797    eastward by 1 second to align with past and present law.
798
799  Changes to commentary
800
801    Add several references for Chile's 1946/1947 transitions, some of
802    which only affected portions of the country.
803
804  Changes to code
805
806    Fix bug when mktime gets confused by truncated TZif files with
807    unspecified local time.  (Problem reported by Almaz Mingaleev.)
808
809    Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
810    (Problem reported by Christos Zoulas.)
811
812    When reading a version 2 or later TZif file, the TZif reader now
813    validates the version 1 header and data block only enough to skip
814    over them, as recommended by RFC 8536 section 4.  Also, the TZif
815    reader no longer mistakenly attempts to parse a version 1 TZIf
816    file header as a TZ string.
817
818    zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
819    when local time and UT cannot be determined for a timestamp.
820
821  Changes to build procedure
822
823    Distribution tarballs now use standard POSIX.1-1988 ustar format
824    instead of GNU format.  Although the formats are almost identical
825    for these tarballs, ustar headers' magic fields contain "ustar"
826    instead of "ustar ", and their version fields contain "00" instead
827    of " ".  The two formats are planned to diverge more significantly
828    for tzdb releases after 2242-03-16 12:56:31 UTC, when the ustar
829    format becomes obsolete and the tarballs switch to pax format, an
830    extension of ustar.  For details about these formats, please see
831    "pax - portable archive interchange", IEEE Std 1003.1-2017,
832    <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13>.
833
834
835Release 2021e - 2021-10-21 18:41:00 -0700
836
837  Changes to future timestamps
838
839    Palestine will fall back 10-29 (not 10-30) at 01:00.
840    (Thanks to P Chan and Heba Hemad.)
841
842
843Release 2021d - 2021-10-15 13:48:18 -0700
844
845  Briefly:
846    Fiji suspends DST for the 2021/2022 season.
847    'zic -r' marks unspecified timestamps with "-00".
848
849  Changes to future timestamps
850
851    Fiji will suspend observance of DST for the 2021/2022 season.
852    Assume for now that it will return next year.  (Thanks to Jashneel
853    Kumar and P Chan.)
854
855  Changes to code
856
857    'zic -r' now uses "-00" time zone abbreviations for intervals
858    with UT offsets that are unspecified due to -r truncation.
859    This implements a change in draft Internet RFC 8536bis.
860
861
862Release 2021c - 2021-10-01 14:21:49 -0700
863
864  Briefly:
865    Revert most 2021b changes to 'backward'.
866    Fix 'zic -b fat' bug in pre-1970 32-bit data.
867    Fix two Link line typos.
868    Distribute SECURITY file.
869
870    This release is intended as a bugfix release, to fix compatibility
871    problems and typos reported since 2021b was released.
872
873  Changes to Link directives
874
875    Revert almost all of 2021b's changes to the 'backward' file,
876    by moving Link directives back to where they were in 2021a.
877    Although 'zic' doesn't care which source file contains a Link
878    directive, some downstream uses ran into trouble with the move.
879    (Problem reported by Stephen Colebourne for Joda-Time.)
880
881    Fix typo that linked Atlantic/Jan_Mayen to the wrong location
882    (problem reported by Chris Walton).
883
884    Fix 'backzone' typo that linked America/Virgin to the wrong
885    location (problem reported by Michael Deckers).
886
887  Changes to code
888
889    Fix a bug in 'zic -b fat' that caused old timestamps to be
890    mishandled in 32-bit-only readers (problem reported by Daniel
891    Fischer).
892
893  Changes to documentation
894
895    Distribute the SECURITY file (problem reported by Andreas Radke).
896
897
898Release 2021b - 2021-09-24 16:23:00 -0700
899
900  Briefly:
901    Jordan now starts DST on February's last Thursday.
902    Samoa no longer observes DST.
903    Merge more location-based Zones whose timestamps agree since 1970.
904    Move some backward-compatibility links to 'backward'.
905    Rename Pacific/Enderbury to Pacific/Kanton.
906    Correct many pre-1993 transitions in Malawi, Portugal, etc.
907    zic now creates each output file or link atomically.
908    zic -L no longer omits the POSIX TZ string in its output.
909    zic fixes for truncation and leap second table expiration.
910    zic now follows POSIX for TZ strings using all-year DST.
911    Fix some localtime crashes and bugs in obscure cases.
912    zdump -v now outputs more-useful boundary cases.
913    tzfile.5 better matches a draft successor to RFC 8536.
914    A new file SECURITY.
915
916    This release is prompted by recent announcements by Jordan and Samoa.
917    It incorporates many other changes that had accumulated since 2021a.
918    However, it omits most proposed changes that merged all Zones
919    agreeing since 1970, as concerns were raised about doing too many of
920    these changes at once.  It does keeps some of these changes in the
921    interest of making tzdb more equitable one step at a time; see
922    "Merge more location-based Zones" below.
923
924  Changes to future timestamps
925
926    Jordan now starts DST on February's last Thursday.
927    (Thanks to Steffen Thorsen.)
928
929    Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
930
931  Changes to zone name
932
933    Rename Pacific/Enderbury to Pacific/Kanton.  When we added
934    Enderbury in 1993, we did not know that it is uninhabited and that
935    Kanton (population two dozen) is the only inhabited location in
936    that timezone.  The old name is now a backward-compatibility link.
937
938  Changes to past timestamps
939
940    Correct many pre-1993 transitions, fixing entries originally
941    derived from Shanks, Whitman, and Mundell.  The fixes include:
942      - Barbados: standard time was introduced in 1911, not 1932; and
943	DST was observed in 1942-1944
944      - Cook Islands: In 1899 they switched from east to west of GMT,
945	celebrating Christmas for two days.  They (and Niue) switched
946	to standard time in 1952, not 1901.
947      - Guyana: corrected LMT for Georgetown; the introduction of
948	standard time in 1911, not 1915; and corrections to 1975 and
949	1992 transitions
950      - Kanton: uninhabited before 1937-08-31
951      - Niue: only observed -11:20 from 1952 through 1964, then went to
952        -11 instead of -11:30
953      - Portugal: DST was observed in 1950
954      - Tonga: corrected LMT; the introduction of standard time in 1945,
955        not 1901; and corrections to the transition from +12:20 to +13
956        in 1961, not 1941
957    Additional fixes to entries in the 'backzone' file include:
958      - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
959      - The Gambia: 1933 and 1942 transitions
960      - Malawi: several 1911 through 1925 transitions
961      - Sierra Leone: several 1913 through 1941 transitions, and DST
962	was NOT observed in 1957 through 1962
963    (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
964    Alois Treindl.)
965
966    Merge more location-based Zones whose timestamps agree since 1970,
967    as pre-1970 timestamps are out of scope.  This is part of a
968    process that has been ongoing since 2013.  This does not affect
969    post-1970 timestamps, and timezone historians who build with 'make
970    PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
971    When merging, keep the most-populous location's data, and move
972    data for other locations to 'backzone' with a backward
973    link in 'backward'.  For example, move America/Creston data to
974    'backzone' with a link in 'backward' from America/Phoenix because
975    the two timezones' timestamps agree since 1970; this change
976    affects some pre-1968 timestamps in America/Creston because
977    Creston and Phoenix disagreed before 1968.  The affected Zones
978    are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
979    America/Creston, America/Curacao, America/Nassau,
980    America/Port_of_Spain, Antarctica/DumontDUrville, and
981    Antarctica/Syowa.
982
983  Changes to maintenance procedure
984
985    The new file SECURITY covers how to report security-related bugs.
986
987    Several backward-compatibility links have been moved to the
988    'backward' file.  These links, which range from Africa/Addis_Ababa
989    to Pacific/Saipan, are only for compatibility with now-obsolete
990    guidelines suggesting an entry for every ISO 3166 code.
991    The intercontinental convenience links Asia/Istanbul and
992    Europe/Nicosia have also been moved to 'backward'.
993
994  Changes to code
995
996    zic now creates each output file or link atomically,
997    possibly by creating a temporary file and then renaming it.
998    This avoids races where a TZ setting would temporarily stop
999    working while zic was installing a replacement file or link.
1000
1001    zic -L no longer omits the POSIX TZ string in its output.
1002    Starting with 2020a, zic -L truncated its output according to the
1003    "Expires" directive or "#expires" comment in the leapseconds file.
1004    The resulting TZif files omitted daylight saving transitions after
1005    the leap second table expired, which led to far less accurate
1006    predictions of times after the expiry.  Although future timestamps
1007    cannot be converted accurately in the presence of leap seconds, it
1008    is more accurate to convert near-future timestamps with a few
1009    seconds error than with an hour error, so zic -L no longer
1010    truncates output in this way.
1011
1012    Instead, when zic -L is given the "Expires" directive, it now
1013    outputs the expiration by appending a no-change entry to the leap
1014    second table.  Although this should work well with most TZif
1015    readers, it does not conform to Internet RFC 8536 and some pickier
1016    clients (including tzdb 2017c through 2021a) reject it, so
1017    "Expires" directives are currently disabled by default.  To enable
1018    them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
1019    this new feature it is marked with a new TZif version number 4,
1020    a format intended to be documented in a successor to RFC 8536.
1021    The old-format "#expires" comments are now treated solely as
1022    comments and have no effect on the TZif files.
1023
1024    zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
1025    that omits leap second information for the range LO..B when LO
1026    falls between two leap seconds A and B.  Instead, it generates a
1027    TZif version 4 file that represents the previously missing
1028    information.
1029
1030    The TZif reader now allows the leap second table to begin with a
1031    correction other than -1 or +1, and to contain adjacent
1032    transitions with equal corrections.  This supports TZif version 4.
1033
1034    The TZif reader now lets leap seconds occur less than 28 days
1035    apart.  This supports possible future TZif extensions.
1036
1037    Fix bug that caused 'localtime' etc. to crash when TZ was
1038    set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
1039    not conform to POSIX but does conform to Internet RFC 8536.
1040
1041    Fix another bug that caused 'localtime' etc. to crash when TZ was
1042    set to a POSIX-conforming but unusual TZ string like
1043    "EST5EDT4,0/0,J365/0", where almost all the year is DST.
1044
1045    Fix yet another bug that caused 'localtime' etc. to mishandle slim
1046    TZif files containing leap seconds after the last explicit
1047    transition in the table, or when handling far-future timestamps
1048    in slim TZif files lacking leap seconds.
1049
1050    Fix localtime misbehavior involving positive leap seconds.
1051    This change affects only behavior for "right" system time,
1052    which contains leap seconds, and only if the UT offset is
1053    not a multiple of 60 seconds when a positive leap second occurs.
1054    (No such timezone exists in tzdb, luckily.)  Without the fix,
1055    the timestamp was ambiguous during a positive leap second.
1056    With the fix, any seconds occurring after a positive leap second
1057    and within the same localtime minute are counted through 60, not
1058    through 59; their UT offset (tm_gmtoff) is the same as before.
1059    Here is how the fix affects timestamps in a timezone with UT
1060    offset +01:23:45 (5025 seconds) and with a positive leap second at
1061    1972-06-30 23:59:60 UTC (78796800):
1062
1063	time_t    without the fix      with the fix
1064	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
1065	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
1066	...
1067	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
1068	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
1069
1070    Fix an unlikely bug that caused 'localtime' etc. to misbehave if
1071    civil time changes a few seconds before time_t wraps around, when
1072    leap seconds are enabled.
1073
1074    Fix bug in zic -r; in some cases, the dummy time type after the
1075    last time transition disagreed with the TZ string, contrary to
1076    Internet RFC 8563 section 3.3.
1077
1078    Fix a bug with 'zic -r @X' when X is a negative leap second that
1079    has a nonnegative correction.  Without the fix, the output file
1080    was truncated so that X appeared to be a positive leap second.
1081    Fix a similar, even less likely bug when truncating at a positive
1082    leap second that has a nonpositive correction.
1083
1084    zic -r now reports an error if given rolling leap seconds, as this
1085    usage has never generally worked and is evidently unused.
1086
1087    zic now generates a POSIX-conforming TZ string for TZif files
1088    where all-year DST is predicted for the indefinite future.
1089    For example, for all-year Eastern Daylight Time, zic now generates
1090    "XXX3EDT4,0/0,J365/23" where it previously generated
1091    "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
1092    noting the possibility of POSIX conformance.)
1093
1094    zic.c no longer requires sys/wait.h (thanks to spazmodius for
1095    noting it wasn't needed).
1096
1097    When reading slim TZif files, zdump no longer mishandles leap
1098    seconds on the rare platforms where time_t counts leap seconds,
1099    fixing a bug introduced in 2014g.
1100
1101    zdump -v now outputs timestamps at boundaries of what localtime
1102    and gmtime can represent, instead of the less useful timestamps
1103    one day after the minimum and one day before the maximum.
1104    (Thanks to Arthur David Olson for prototype code, and to Manuela
1105    Friedrich for debugging help.)
1106
1107    zdump's -c and -t options are now consistently inclusive for the
1108    lower time bound and exclusive for the upper.  Formerly they were
1109    inconsistent.  (Confusion noted by Martin Burnicki.)
1110
1111  Changes to build procedure
1112
1113    You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
1114    non-POSIX hosts where malloc doesn't set errno.
1115    (Problem reported by Jan Engelhardt.)
1116
1117  Changes to documentation
1118
1119    tzfile.5 better matches a draft successor to RFC 8536
1120    <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.
1121
1122
1123Release 2021a - 2021-01-24 10:54:57 -0800
1124
1125  Changes to future timestamps
1126
1127    South Sudan changes from +03 to +02 on 2021-02-01 at 00:00.
1128    (Thanks to Steffen Thorsen.)
1129
1130
1131Release 2020f - 2020-12-29 00:17:46 -0800
1132
1133  Change to build procedure
1134
1135    'make rearguard_tarballs' no longer generates a bad rearguard.zi,
1136    fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
1137
1138
1139Release 2020e - 2020-12-22 15:14:34 -0800
1140
1141  Briefly:
1142    Volgograd switches to Moscow time on 2020-12-27 at 02:00.
1143
1144  Changes to future timestamps
1145
1146    Volgograd changes time zone from +04 to +03 on 2020-12-27 at 02:00.
1147    (Thanks to Alexander Krivenyshev and Stepan Golosunov.)
1148
1149  Changes to past timestamps
1150
1151    Correct many pre-1986 transitions, fixing entries originally
1152    derived from Shanks.  The fixes include:
1153      - Australia: several 1917 through 1971 transitions
1154      - The Bahamas: several 1941 through 1945 transitions
1155      - Bermuda: several 1917 through 1956 transitions
1156      - Belize: several 1942 through 1968 transitions
1157      - Ghana: several 1915 through 1956 transitions
1158      - Israel and Palestine: several 1940 through 1985 transitions
1159      - Kenya and adjacent: several 1908 through 1960 transitions
1160      - Nigeria and adjacent: correcting LMT in Lagos, and several 1905
1161        through 1919 transitions
1162      - Seychelles: the introduction of standard time in 1907, not 1906
1163      - Vanuatu: DST in 1973-1974, and a corrected 1984 transition
1164    (Thanks to P Chan.)
1165
1166    Because of the Australia change, Australia/Currie (King Island) is
1167    no longer needed, as it is identical to Australia/Hobart for all
1168    timestamps since 1970 and was therefore created by mistake.
1169    Australia/Currie has been moved to the 'backward' file and its
1170    corrected data moved to the 'backzone' file.
1171
1172  Changes to past time zone abbreviations and DST flags
1173
1174    To better match legislation in Turks and Caicos, the 2015 shift to
1175    year-round observance of -04 is now modeled as AST throughout before
1176    returning to Eastern Time with US DST in 2018, rather than as
1177    maintaining EDT until 2015-11-01.  (Thanks to P Chan.)
1178
1179  Changes to documentation
1180
1181    The zic man page now documents zic's coalescing of transitions
1182    when a zone falls back just before DST springs forward.
1183
1184
1185Release 2020d - 2020-10-21 11:24:13 -0700
1186
1187  Briefly:
1188    Palestine ends DST earlier than predicted, on 2020-10-24.
1189
1190  Changes to past and future timestamps
1191
1192    Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
1193    as previously predicted (thanks to Sharef Mustafa.)  Its
1194    2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
1195    Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
1196    its spring 2020 transition was on March 28 at 00:00, not March 27
1197    (thanks to Pierre Cashon.)  This affects Asia/Gaza and
1198    Asia/Hebron.  Assume future spring and fall transitions will be on
1199    the Saturday preceding the last Sunday of March and October,
1200    respectively.
1201
1202
1203Release 2020c - 2020-10-16 11:15:53 -0700
1204
1205  Briefly:
1206    Fiji starts DST later than usual, on 2020-12-20.
1207
1208  Changes to future timestamps
1209
1210    Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
1211    previously predicted.  DST will still end on 2021-01-17.
1212    (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
1213    the later-than-usual start date is a one-time departure from the
1214    recent pattern.
1215
1216  Changes to build procedure
1217
1218    Rearguard tarballs now contain an empty file pacificnew.
1219    Some older downstream software expects this file to exist.
1220    (Problem reported by Mike Cullinan.)
1221
1222
1223Release 2020b - 2020-10-06 18:35:04 -0700
1224
1225  Briefly:
1226    Revised predictions for Morocco's changes starting in 2023.
1227    Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
1228    Macquarie Island has stayed in sync with Tasmania since 2011.
1229    Casey, Antarctica is at +08 in winter and +11 in summer.
1230    zic no longer supports -y, nor the TYPE field of Rules.
1231
1232  Changes to future timestamps
1233
1234    Morocco's spring-forward after Ramadan is now predicted to occur
1235    no sooner than two days after Ramadan, instead of one day.
1236    (Thanks to Milamber.)  The first altered prediction is for 2023,
1237    now predicted to spring-forward on April 30 instead of April 23.
1238
1239  Changes to past and future timestamps
1240
1241   Casey Station, Antarctica has been using +08 in winter and +11 in
1242   summer since 2018.  The most recent transition from +08 to +11 was
1243   2020-10-04 00:01.  Also, Macquarie Island has been staying in
1244   sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
1245
1246  Changes to past and future time zone abbreviations and DST flags
1247
1248    Canada's Yukon, represented by America/Whitehorse and
1249    America/Dawson, changes its time zone rules from -08/-07 to
1250    permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
1251    This change affects only the time zone abbreviation (MST vs PDT)
1252    and daylight saving flag for the period between the two dates.
1253    (Thanks to Andrew G. Smith.)
1254
1255  Changes to past timestamps
1256
1257    Correct several transitions for Hungary for 1918/1983.
1258    For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
1259    (Thanks to Géza Nyáry.)  Also, the 1890 transition to standard
1260    time was on 11-01, not 10-01 (thanks to Michael Deckers).
1261
1262    The 1891 French transition was on March 16, not March 15.  The
1263    1911-03-11 French transition was at midnight, not a minute later.
1264    Monaco's transitions were on 1892-06-01 and 1911-03-29, not
1265    1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
1266
1267  Changes to code
1268
1269    Support for zic's long-obsolete '-y YEARISTYPE' option has been
1270    removed and, with it, so has support for the TYPE field in Rule
1271    lines, which is now reserved for compatibility with earlier zic.
1272    These features were previously deprecated in release 2015f.
1273    (Thanks to Tim Parenti.)
1274
1275    zic now defaults to '-b slim' instead of to '-b fat'.
1276
1277    zic's new '-l -' and '-p -' options uninstall any existing
1278    localtime and posixrules files, respectively.
1279
1280    The undocumented and ineffective tzsetwall function has been
1281    removed.
1282
1283  Changes to build procedure
1284
1285    The Makefile now defaults POSIXRULES to '-', so the posixrules
1286    feature (obsolete as of 2019b) is no longer installed by default.
1287
1288  Changes to documentation and commentary
1289
1290    The long-obsolete files pacificnew, systemv, and yearistype.sh have
1291    been removed from the distribution.  (Thanks to Tim Parenti.)
1292
1293
1294Release 2020a - 2020-04-23 16:03:47 -0700
1295
1296  Briefly:
1297    Morocco springs forward on 2020-05-31, not 2020-05-24.
1298    Canada's Yukon advanced to -07 year-round on 2020-03-08.
1299    America/Nuuk renamed from America/Godthab.
1300    zic now supports expiration dates for leap second lists.
1301
1302  Changes to future timestamps
1303
1304    Morocco's second spring-forward transition in 2020 will be May 31,
1305    not May 24 as predicted earlier.  (Thanks to Semlali Naoufal.)
1306    Adjust future-year predictions to use the first Sunday after the
1307    day after Ramadan, not the first Sunday after Ramadan.
1308
1309    Canada's Yukon, represented by America/Whitehorse and
1310    America/Dawson, advanced to -07 year-round, beginning with its
1311    spring-forward transition on 2020-03-08, and will not fall back on
1312    2020-11-01.  Although a government press release calls this
1313    "permanent Pacific Daylight Saving Time", we prefer MST for
1314    consistency with nearby Dawson Creek, Creston, and Fort Nelson.
1315    (Thanks to Tim Parenti.)
1316
1317  Changes to past timestamps
1318
1319    Shanghai observed DST in 1919.  (Thanks to Phake Nick.)
1320
1321  Changes to timezone identifiers
1322
1323    To reflect current usage in English better, America/Godthab has
1324    been renamed to America/Nuuk.  A backwards-compatibility link
1325    remains for the old name.
1326
1327  Changes to code
1328
1329    localtime.c no longer mishandles timestamps after the last
1330    transition in a TZif file with leap seconds and with daylight
1331    saving time transitions projected into the indefinite future.
1332    For example, with TZ='America/Los_Angeles' with leap seconds,
1333    zdump formerly reported a DST transition on 2038-03-14
1334    from 01:59:32.999... to 02:59:33 instead of the correct transition
1335    from 01:59:59.999... to 03:00:00.
1336
1337    zic -L now supports an Expires line in the leapseconds file, and
1338    truncates the TZif output accordingly.  This propagates leap
1339    second expiration information into the TZif file, and avoids the
1340    abovementioned localtime.c bug as well as similar bugs present in
1341    many client implementations.  If no Expires line is present, zic
1342    -L instead truncates the TZif output based on the #expires comment
1343    present in leapseconds files distributed by tzdb 2018f and later;
1344    however, this usage is obsolescent.  For now, the distributed
1345    leapseconds file has an Expires line that is commented out, so
1346    that the file can be fed to older versions of zic which ignore the
1347    commented-out line.  Future tzdb distributions are planned to
1348    contain a leapseconds file with an Expires line.
1349
1350    The configuration macros HAVE_TZNAME and USG_COMPAT should now be
1351    set to 1 if the system library supports the feature, and 2 if not.
1352    As before, these macros are nonzero if tzcode should support the
1353    feature, zero otherwise.
1354
1355    The configuration macro ALTZONE now has the same values with the
1356    same meaning as HAVE_TZNAME and USG_COMPAT.
1357
1358    The code's defense against CRLF in leap-seconds.list is now
1359    portable to POSIX awk.  (Problem reported by Deborah Goldsmith.)
1360
1361    Although the undocumented tzsetwall function is not changed in
1362    this release, it is now deprecated in preparation for removal in
1363    future releases.  Due to POSIX requirements, tzsetwall has not
1364    worked for some time.  Any code that uses it should instead use
1365    tzalloc(NULL) or, if portability trumps thread-safety, should
1366    unset the TZ environment variable.
1367
1368  Changes to commentary
1369
1370    The Îles-de-la-Madeleine and the Listuguj reserve are noted as
1371    following America/Halifax, and comments about Yukon's "south" and
1372    "north" have been corrected to say "east" and "west".  (Thanks to
1373    Jeffery Nichols.)
1374
1375
1376Release 2019c - 2019-09-11 08:59:48 -0700
1377
1378  Briefly:
1379    Fiji observes DST from 2019-11-10 to 2020-01-12.
1380    Norfolk Island starts observing Australian-style DST.
1381
1382  Changes to future timestamps
1383
1384    Fiji's next DST transitions will be 2019-11-10 and 2020-01-12
1385    instead of 2019-11-03 and 2020-01-19.  (Thanks to Raymond Kumar.)
1386    Adjust future guesses accordingly.
1387
1388    Norfolk Island will observe Australian-style DST starting in
1389    spring 2019.  The first transition is on 2019-10-06.  (Thanks to
1390    Kyle Czech and Michael Deckers.)
1391
1392  Changes to past timestamps
1393
1394    Many corrections to time in Turkey from 1940 through 1985.
1395    (Thanks to Oya Vulaş via Alois Treindl, and to Kıvanç Yazan.)
1396
1397    The Norfolk Island 1975-03-02 transition was at 02:00 standard
1398    time, not 02:00 DST.  (Thanks to Michael Deckers.)
1399
1400    South Korea observed DST from 1948 through 1951.  Although this
1401    info was supposed to appear in release 2014j, a typo inadvertently
1402    suppressed the change.  (Thanks to Alois Treindl.)
1403
1404    Detroit observed DST in 1967 and 1968 following the US DST rules,
1405    except that its 1967 DST began on June 14 at 00:01.  (Thanks to
1406    Alois Treindl for pointing out that the old data entries were
1407    probably wrong.)
1408
1409    Fix several errors in pre-1970 transitions in Perry County, IN.
1410    (Thanks to Alois Treindl for pointing out the 1967/9 errors.)
1411
1412    Edmonton did not observe DST in 1967 or 1969.  In 1946 Vancouver
1413    ended DST on 09-29 not 10-13, and Vienna ended DST on 10-07 not
1414    10-06.  In 1945 Königsberg (now Kaliningrad) switched from +01/+02
1415    to +02/+03 on 04-10 not 01-01, and its +02/+03 is abbreviated
1416    EET/EEST, not CET/CEST.  (Thanks to Alois Treindl.)  In 1946
1417    Königsberg switched to +03 on 04-07 not 01-01.
1418
1419    In 1946 Louisville switched from CST to CDT on 04-28 at 00:01, not
1420    01-01 at 00:00.  (Thanks to Alois Treindl and Michael Deckers.)
1421    Also, it switched from CST to CDT on 1950-04-30, not 1947-04-27.
1422
1423    The 1892-05-01 transition in Brussels was at 00:17:30, not at noon.
1424    (Thanks to Michael Deckers.)
1425
1426  Changes to past time zone abbreviations and DST flags
1427
1428    Hong Kong Winter Time, observed from 1941-10-01 to 1941-12-25,
1429    is now flagged as DST and is abbreviated HKWT not HKT.
1430
1431  Changes to code
1432
1433    leapseconds.awk now relies only on its input data, rather than
1434    also relying on its comments.  (Inspired by code from Dennis
1435    Ferguson and Chris Woodbury.)
1436
1437    The code now defends against CRLFs in leap-seconds.list.
1438    (Thanks to Brian Inglis and Chris Woodbury.)
1439
1440  Changes to documentation and commentary
1441
1442    theory.html discusses leap seconds.  (Thanks to Steve Summit.)
1443
1444    Nashville's newspapers dueled about the time of day in the 1950s.
1445    (Thanks to John Seigenthaler.)
1446
1447    Liechtenstein observed Swiss DST in 1941/2.
1448    (Thanks to Alois Treindl.)
1449
1450
1451Release 2019b - 2019-07-01 00:09:53 -0700
1452
1453  Briefly:
1454    Brazil no longer observes DST.
1455    'zic -b slim' outputs smaller TZif files; please try it out.
1456    Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
1457
1458  Changes to future timestamps
1459
1460    Brazil has canceled DST and will stay on standard time indefinitely.
1461    (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
1462    Oliveira.)
1463
1464    Predictions for Morocco now go through 2087 instead of 2037, to
1465    work around a problem on newlib when using TZif files output by
1466    zic 2019a or earlier.  (Problem reported by David Gauchard.)
1467
1468  Changes to past and future timestamps
1469
1470    Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
1471    at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
1472    future transitions to be March's last Friday at 00:00.
1473
1474  Changes to past timestamps
1475
1476    Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
1477    03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
1478    not 09-15 at 00:00.  In 1946 its spring-forward transition was on
1479    04-21 at 00:00, not the previous day at 03:30.  From 1946 through
1480    1952 its fall-back transitions occurred at 04:30, not at 03:30.
1481    In 1947 its fall-back transition was on 11-30, not 12-30.
1482    (Thanks to P Chan.)
1483
1484  Changes to past time zone abbreviations
1485
1486    Italy's 1866 transition to Rome Mean Time was on December 12, not
1487    September 22.  This affects only the time zone abbreviation for
1488    Europe/Rome between those dates.  (Thanks to Stephen Trainor and
1489    Luigi Rosa.)
1490
1491  Changes affecting metadata only
1492
1493    Add info about the Crimea situation in zone1970.tab and zone.tab.
1494    (Problem reported by Serhii Demediuk.)
1495
1496  Changes to code
1497
1498    zic's new -b option supports a way to control data bloat and to
1499    test for year-2038 bugs in software that reads TZif files.
1500    'zic -b fat' and 'zic -b slim' generate larger and smaller output;
1501    for example, changing from fat to slim shrinks the Europe/London
1502    file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
1503    files represent the same set of timestamps and use the same TZif
1504    format as documented in tzfile(5) and in Internet RFC 8536.
1505    Fat format attempts to work around bugs or incompatibilities in
1506    older software, notably software that mishandles 64-bit TZif data
1507    or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
1508    Slim format is more efficient and does not work around 64-bit bugs
1509    or obsolete TZ strings.  Currently zic defaults to fat format
1510    unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
1511    out-of-the-box default is intended to change in future releases
1512    as the buggy software often mishandles timestamps anyway.
1513
1514    zic no longer treats a set of rules ending in 2037 specially.
1515    Previously, zic assumed that such a ruleset meant that future
1516    timestamps could not be predicted, and therefore omitted a
1517    POSIX-like TZ string in the TZif output.  The old behavior is no
1518    longer needed for current tzdata, and caused problems with newlib
1519    when used with older tzdata (reported by David Gauchard).
1520
1521    zic no longer generates some artifact transitions.  For example,
1522    Europe/London no longer has a no-op transition in January 1996.
1523
1524  Changes to build procedure
1525
1526    tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
1527    by a percent or so.
1528
1529  Changes to documentation and commentary
1530
1531    The Makefile now documents the POSIXRULES macro as being obsolete,
1532    and similarly, zic's -p POSIXRULES option is now documented as
1533    being obsolete.  Although the POSIXRULES feature still exists and
1534    works as before, in practice it is rarely used for its intended
1535    purpose, and it does not work either in the default reference
1536    implementation (for timestamps after 2037) or in common
1537    implementations such as GNU/Linux (for contemporary timestamps).
1538    Since POSIXRULES was designed primarily as a temporary transition
1539    facility for System V platforms that died off decades ago, it is
1540    being decommissioned rather than institutionalized.
1541
1542    New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
1543
1544
1545Release 2019a - 2019-03-25 22:01:33 -0700
1546
1547  Briefly:
1548    Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
1549    Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
1550
1551  Changes to past and future timestamps
1552
1553    Palestine will not start DST until 2019-03-30, instead of 2019-03-23 as
1554    previously predicted.  Adjust our prediction by guessing that spring
1555    transitions will be between 24 and 30 March, which matches recent practice
1556    since 2016.  (Thanks to Even Scharning and Tim Parenti.)
1557
1558    Metlakatla ended its observance of Pacific standard time,
1559    rejoining Alaska Time, on 2019-01-20 at 02:00.  (Thanks to Ryan
1560    Stanley and Tim Parenti.)
1561
1562  Changes to past timestamps
1563
1564    Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
1565    (Thanks to Alois Treindl and Isaac Starkman.)
1566
1567  Changes to time zone abbreviations
1568
1569    Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
1570    of being a separate zone that generates the abbreviation "UCT",
1571    which nowadays is typically a typo.  (Problem reported by Isiah
1572    Meadows.)
1573
1574  Changes to code
1575
1576    zic now has an -r option to limit the time range of output data.
1577    For example, 'zic -r @1000000000' limits the output data to
1578    timestamps starting 1000000000 seconds after the Epoch.
1579    This helps shrink output size and can be useful for applications
1580    not needing the full timestamp history, such as TZDIST truncation;
1581    see Internet RFC 8536 section 5.1.  (Inspired by a feature request
1582    from Christopher Wong, helped along by bug reports from Wong and
1583    from Tim Parenti.)
1584
1585  Changes to documentation
1586
1587    Mention Internet RFC 8536 (February 2019), which documents TZif.
1588
1589    tz-link.html now cites tzdata-meta
1590    <https://tzdata-meta.timtimeonline.com/>.
1591
1592
1593Release 2018i - 2018-12-30 11:05:43 -0800
1594
1595  Briefly:
1596    São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.
1597
1598  Changes to future timestamps
1599
1600    Due to a change in government, São Tomé and Príncipe switches back
1601    from +01 to +00 on 2019-01-01 at 02:00.  (Thanks to Vadim
1602    Nasardinov and Michael Deckers.)
1603
1604
1605Release 2018h - 2018-12-23 17:59:32 -0800
1606
1607  Briefly:
1608    Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
1609    New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
1610    Metlakatla, Alaska observes PST this winter only.
1611    Guess Morocco will continue to adjust clocks around Ramadan.
1612    Add predictions for Iran from 2038 through 2090.
1613
1614  Changes to future timestamps
1615
1616    Guess that Morocco will continue to fall back just before and
1617    spring forward just after Ramadan, the practice since 2012.
1618    (Thanks to Maamar Abdelkader.)  This means Morocco will observe
1619    negative DST during Ramadan in main and vanguard formats, and in
1620    rearguard format it stays in the +00 timezone and observes
1621    ordinary DST in all months other than Ramadan.  As before, extend
1622    this guesswork to the year 2037.  As a consequence, Morocco is
1623    scheduled to observe three DST transitions in some Gregorian years
1624    (e.g., 2033) due to the mismatch between the Gregorian and Islamic
1625    calendars.
1626
1627    The table of exact transitions for Iranian DST has been extended.
1628    It formerly cut off before the year 2038 in a nod to 32-bit time_t.
1629    It now cuts off before 2091 as there is doubt about how the Persian
1630    calendar will treat 2091.  This change predicts DST transitions in
1631    2038-9, 2042-3, and 2046-7 to occur one day later than previously
1632    predicted.  As before, post-cutoff transitions are approximated.
1633
1634  Changes to past and future timestamps
1635
1636    Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
1637    +05 on 2018-12-21.  This is a zone split as Qostanay (aka
1638    Kostanay) did not switch, so create a zone Asia/Qostanay.
1639
1640    Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
1641    It did not change clocks that day and remains on -08 this winter.
1642    (Thanks to Ryan Stanley.)  It will revert to the usual Alaska
1643    rules next spring, so this change affects only timestamps
1644    from 2018-11-04 through 2019-03-10.
1645
1646  Change to past timestamps
1647
1648    Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
1649    not 00:00.  I transcribed the time incorrectly from Shanks.
1650    (Thanks to Phake Nick.)
1651
1652    Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
1653    (Thanks to Phake Nick.)
1654
1655    Guam observed DST irregularly from 1959 through 1977.
1656    (Thanks to Phake Nick.)
1657
1658    Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
1659    10-01 changed standard time to +08:30 (not +08).  Its transition
1660    back to +08 after WWII was on 1945-09-15, not the previous day.
1661    Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
1662    (Thanks to Phake Nick, Steve Allen, and Joseph Myers.)  Also,
1663    its 1952 fallback was on 11-02 (not 10-25).
1664
1665    This release contains many changes to timestamps before 1946 due
1666    to Japanese possession or occupation of Pacific/Chuuk,
1667    Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
1668    Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
1669    (Thanks to Phake Nick.)
1670
1671    Assume that the Spanish East Indies was like the Philippines and
1672    observed American time until the end of 1844.  This affects
1673    Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.
1674
1675  Changes to past tm_isdst flags
1676
1677    For the recent Morocco change, the tm_isdst flag should be 1 from
1678    2018-10-27 00:00 to 2018-10-28 03:00.  (Thanks to Michael Deckers.)
1679    Give a URL to the official decree.  (Thanks to Matt Johnson.)
1680
1681
1682Release 2018g - 2018-10-26 22:22:45 -0700
1683
1684  Briefly:
1685    Morocco switches to permanent +01 on 2018-10-28.
1686
1687  Changes to future timestamps
1688
1689    Morocco switches from +00/+01 to permanent +01 effective 2018-10-28,
1690    so its clocks will not fall back as previously scheduled.
1691    (Thanks to Mohamed Essedik Najd and Brian Inglis.)
1692
1693  Changes to code
1694
1695    When generating TZif files with leap seconds, zic no longer uses a
1696    format that trips up older 32-bit clients, fixing a bug introduced
1697    in 2018f.  (Reported by Daniel Fischer.)  Also, the zic workaround
1698    for QTBUG-53071 now also works for TZif files with leap seconds.
1699
1700    The translator to rearguard format now rewrites the line
1701    "Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S" to
1702    "Rule Japan 1948 1951 - Sep Sun>=9  1:00 0 S".
1703    This caters to zic before 2007 and to Oracle TZUpdater 2.2.0
1704    and earlier.  (Reported by Christos Zoulas.)
1705
1706  Changes to past time zone abbreviations
1707
1708    Change HDT to HWT/HPT for WWII-era abbreviations in Hawaii.
1709    This reverts to 2011h, as the abbreviation change in 2011i was
1710    likely inadvertent.
1711
1712  Changes to documentation
1713
1714    tzfile.5 has new sections on interoperability issues.
1715
1716
1717Release 2018f - 2018-10-18 00:14:18 -0700
1718
1719  Briefly:
1720  Volgograd moves from +03 to +04 on 2018-10-28.
1721  Fiji ends DST 2019-01-13, not 2019-01-20.
1722  Most of Chile changes DST dates, effective 2019-04-06.
1723
1724  Changes to future timestamps
1725
1726    Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
1727    (Thanks to Alexander Fetisov and Stepan Golosunov.)
1728
1729    Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
1730    predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
1731    accordingly.
1732
1733    Most of Chile will end DST on the first Saturday in April at 24:00 mainland
1734    time, and resume DST on the first Saturday in September at 24:00 mainland
1735    time.  The changes are effective from 2019-04-06, and do not affect the
1736    Magallanes region modeled by America/Punta_Arenas.  (Thanks to Juan Correa
1737    and Tim Parenti.)  Adjust future predictions accordingly.
1738
1739  Changes to past timestamps
1740
1741    The 2018-05-05 North Korea 30-minute time zone change took place
1742    at 23:30 the previous day, not at 00:00 that day.
1743
1744    China's 1988 spring-forward transition was on April 17, not
1745    April 10.  Its DST transitions in 1986/91 were at 02:00, not 00:00.
1746    (Thanks to P Chan.)
1747
1748    Fix several issues for Macau before 1992.  Macau's pre-1904 LMT
1749    was off by 10 s.  Macau switched to +08 in 1904 not 1912, and
1750    temporarily switched to +09/+10 during World War II.  Macau
1751    observed DST in 1942/79, not 1961/80, and there were several
1752    errors for transition times and dates.  (Thanks to P Chan.)
1753
1754    The 1948-1951 fallback transitions in Japan were at 25:00 on
1755    September's second Saturday, not at 24:00.  (Thanks to Phake Nick.)
1756    zic turns this into 01:00 on the day after September's second
1757    Saturday, which is the best that POSIX or C platforms can do.
1758
1759    Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
1760    paper by Li Yu, replacing more-questionable data from Shanks.
1761
1762  Changes to time zone abbreviations
1763
1764    Use "PST" and "PDT" for Philippine time.  (Thanks to Paul Goyette.)
1765
1766  Changes to code
1767
1768    zic now always generates TZif files where time type 0 is used for
1769    timestamps before the first transition.  This simplifies the
1770    reading of TZif files and should not affect behavior of existing
1771    TZif readers because the same set of time types is used; only
1772    their internal indexes may have changed.  This affects only the
1773    legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
1774    EET, which previously used nonzero types for these timestamps.
1775
1776    Because of the type 0 change, zic no longer outputs a dummy
1777    transition at time -2**59 (before the Big Bang), as clients should
1778    no longer need this to handle historical timestamps correctly.
1779    This reverts a change introduced in 2013d and shrinks most TZif
1780    files by a few bytes.
1781
1782    zic now supports negative time-of-day in Rule and Leap lines, e.g.,
1783    "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
1784    occurs at 18:00 on the Saturday before the last Sunday in April.
1785    This behavior was documented in 2018a but the code did not
1786    entirely match the documentation.
1787
1788    localtime.c no longer requires at least one time type in TZif
1789    files that lack transitions or have a POSIX-style TZ string.  This
1790    future-proofs the code against possible future extensions to the
1791    format that would allow TZif files with POSIX-style TZ strings and
1792    without transitions or time types.
1793
1794    A read-access subscript error in localtime.c has been fixed.
1795    It could occur only in TZif files with timecnt == 0, something that
1796    does not happen in practice now but could happen in future versions.
1797
1798    localtime.c no longer ignores TZif POSIX-style TZ strings that
1799    specify only standard time.  Instead, these TZ strings now
1800    override the default time type for timestamps after the last
1801    transition (or for all timestamps if there are no transitions),
1802    just as DST strings specifying DST have always done.
1803
1804    leapseconds.awk now outputs "#updated" and "#expires" comments,
1805    and supports leap seconds at the ends of months other than June
1806    and December.  (Inspired by suggestions from Chris Woodbury.)
1807
1808  Changes to documentation
1809
1810    New restrictions: A Rule name must start with a character that
1811    is neither an ASCII digit nor "-" nor "+", and an unquoted name
1812    should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
1813    The latter restriction makes room for future extensions (a
1814    possibility noted by Tom Lane).
1815
1816    tzfile.5 now documents what time types apply before the first and
1817    after the last transition, if any.
1818
1819    Documentation now uses the spelling "timezone" for a TZ setting
1820    that determines timestamp history, and "time zone" for a
1821    geographic region currently sharing the same standard time.
1822
1823    The name "TZif" is now used for the tz binary data format.
1824
1825    tz-link.htm now mentions the A0 TimeZone Migration utilities.
1826    (Thanks to Aldrin Martoq for the link.)
1827
1828  Changes to build procedure
1829
1830    New 'make' target 'rearguard_tarballs' to build the rearguard
1831    tarball only.  This is a convenience on platforms that lack lzip
1832    if you want to build the rearguard tarball.  (Problem reported by
1833    Deborah Goldsmith.)
1834
1835    tzdata.zi is now more stable from release to release.  (Problem
1836    noted by Tom Lane.)  It is also a bit shorter.
1837
1838    tzdata.zi now can contain comment lines documenting configuration
1839    information, such as which data format was selected, which input
1840    files were used, and how leap seconds are treated.  (Problems
1841    noted by Lester Caine and Brian Inglis.)  If the Makefile defaults
1842    are used these comment lines are absent, for backward
1843    compatibility.  A redistributor intending to alter its copy of the
1844    files should also append "-LABEL" to the 'version' file's first
1845    line, where "LABEL" identifies the redistributor's change.
1846
1847
1848Release 2018e - 2018-05-01 23:42:51 -0700
1849
1850  Briefly:
1851
1852    North Korea switches back to +09 on 2018-05-05.
1853    The main format uses negative DST again, for Ireland etc.
1854    'make tarballs' now also builds a rearguard tarball.
1855    New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
1856
1857  Changes to past and future timestamps
1858
1859    North Korea switches back from +0830 to +09 on 2018-05-05.
1860    (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
1861    and Tim Parenti.)
1862
1863    Bring back the negative-DST changes of 2018a, except be more
1864    compatible with data parsers that do not support negative DST.
1865    Also, this now affects historical timestamps in Namibia and the
1866    former Czechoslovakia, not just Ireland.  The main format now uses
1867    negative DST to model timestamps in Europe/Dublin (from 1971 on),
1868    Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
1869    does not affect UT offsets, only time zone abbreviations and the
1870    tm_isdst flag.  Also, this does not affect rearguard or vanguard
1871    formats; effectively the main format now uses vanguard instead of
1872    rearguard format.  Data parsers that do not support negative DST
1873    can still use data from the rearguard tarball described below.
1874
1875  Changes to build procedure
1876
1877    The command 'make tarballs' now also builds the tarball
1878    tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
1879    except that it uses rearguard format intended for trailing-edge
1880    data parsers.
1881
1882  Changes to data format and to code
1883
1884    The SAVE column of Rule and Zone lines can now have an 's' or 'd'
1885    suffix, which specifies whether the adjusted time is standard time
1886    or daylight saving time.  If no suffix is given, daylight saving
1887    time is used if and only if the SAVE column is nonzero; this is
1888    the longstanding behavior.  Although this new feature is not used
1889    in tzdata, it could be used to specify the legal time in Namibia
1890    1994-2017, as opposed to the popular time (see below).
1891
1892  Changes to past timestamps
1893
1894    From 1994 through 2017 Namibia observed DST in winter, not summer.
1895    That is, it used negative DST, as Ireland still does.  This change
1896    does not affect UTC offsets; it affects only the tm_isdst flag and
1897    the abbreviation used during summer, which is now CAT, not WAST.
1898    Although (as noted by Michael Deckers) summer and winter time were
1899    both simply called "standard time" in Namibian law, in common
1900    practice winter time was considered to be DST (as noted by Stephen
1901    Colebourne).  The full effect of this change is only in vanguard
1902    and main format; in rearguard format, the tm_isdst flag is still
1903    zero in winter and nonzero in summer.
1904
1905    In 1946/7 Czechoslovakia also observed negative DST in winter.
1906    The full effect of this change is only in vanguard and main
1907    formats; in rearguard format, it is modeled as plain GMT without
1908    daylight saving.  Also, the dates of some 1944/5 DST transitions
1909    in Czechoslovakia have been changed.
1910
1911
1912Release 2018d - 2018-03-22 07:05:46 -0700
1913
1914  Briefly:
1915
1916  Palestine starts DST a week earlier in 2018.
1917  Add support for vanguard and rearguard data consumers.
1918  Add subsecond precision to source data format, though not to data.
1919
1920  Changes to future timestamps
1921
1922    In 2018, Palestine starts DST on March 24, not March 31.
1923    Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
1924
1925  Changes to past and future timestamps
1926
1927    Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
1928    at 04:00.  (Thanks to Steffen Thorsen.)
1929
1930  Changes to past timestamps
1931
1932    Historical transitions for Uruguay, represented by
1933    America/Montevideo, have been updated per official legal documents,
1934    replacing previous data mainly originating from the inventions of
1935    Shanks & Pottenger.  This has resulted in adjustments ranging from
1936    30 to 90 minutes in either direction over at least two dozen
1937    distinct periods ranging from one day to several years in length.
1938    A mere handful of pre-1991 transitions are unaffected; data since
1939    then has come from more reliable contemporaneous reporting.  These
1940    changes affect various timestamps in 1920-1923, 1936, 1939,
1941    1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
1942    Additionally, Uruguay's pre-standard-time UT offset has been
1943    adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
1944    match the location of the Observatory of the National Meteorological
1945    Institute in Montevideo.
1946    (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
1947
1948    East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
1949    (Thanks to Kerry Shetline.)
1950
1951    Fix the 1912-01-01 transition for Portugal and its colonies.
1952    This transition was at 00:00 according to the new UT offset, not
1953    according to the old one.  Also assume that Cape Verde switched on
1954    the same date as the rest, not in 1907.  This affects
1955    Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
1956    Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
1957    (Thanks to Michael Deckers.)
1958
1959    Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
1960    Turks & Caicos.
1961
1962  Changes to past time zone abbreviations
1963
1964    MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
1965    is no clock change associated with the transition.
1966
1967  Changes to build procedure
1968
1969    The new DATAFORM macro in the Makefile lets the installer choose
1970    among three source data formats.  The idea is to lessen downstream
1971    disruption when data formats are improved.
1972
1973    * DATAFORM=vanguard installs from the latest, bleeding-edge
1974      format.  DATAFORM=main (the default) installs from the format
1975      used in the 'africa' etc. files.  DATAFORM=rearguard installs
1976      from a trailing-edge format.  Eventually, elements of today's
1977      vanguard format should move to the main format, and similarly
1978      the main format's features should eventually move to the
1979      rearguard format.
1980
1981    * In the current version, the main and rearguard formats are
1982      identical and match that of 2018c, so this change does not
1983      affect default behavior.  The vanguard format currently contains
1984      one feature not in the main format: negative SAVE values.  This
1985      improves support for Ireland, which uses Irish Standard Time
1986      (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
1987      supported negative SAVE values for decades, and this feature
1988      should move to the main format soon.  However, it will not move
1989      to the rearguard format for quite some time because some
1990      downstream parsers do not support it.
1991
1992    * The build procedure constructs three files vanguard.zi, main.zi,
1993      and rearguard.zi, one for each format.  Although the files
1994      represent essentially the same data, they may have minor
1995      discrepancies that users are not likely to notice.  The files
1996      are intended for downstream data consumers and are not
1997      installed.  Zoneinfo parsers that do not support negative SAVE values
1998      should start using rearguard.zi, so that they will be unaffected
1999      when the negative-DST feature moves from vanguard to main.
2000      Bleeding-edge Zoneinfo parsers that support the new features
2001      already can use vanguard.zi; in this respect, current tzcode is
2002      bleeding-edge.
2003
2004    The Makefile should now be safe for parallelized builds, and 'make
2005    -j to2050new.tzs' is now much faster on a multiprocessor host
2006    with GNU Make.
2007
2008    When built with -DSUPPRESS_TZDIR, the tzcode library no longer
2009    prepends TZDIR/ to file names that do not begin with '/'.  This is
2010    not recommended for general use, due to its security implications.
2011    (From a suggestion by Manuela Friedrich.)
2012
2013  Changes to code
2014
2015    zic now accepts subsecond precision in expressions like
2016    00:19:32.13, which is approximately the legal time of the
2017    Netherlands from 1835 to 1937.  However, because it is
2018    questionable whether the few recorded uses of non-integer offsets
2019    had subsecond precision in practice, there are no plans for tzdata
2020    to use this feature.  (Thanks to Steve Allen for pointing out
2021    the limitations of historical data in this area.)
2022
2023    The code is a bit more portable to MS-Windows.  Installers can
2024    compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
2025    reserve identifiers like 'localtime'.  (Thanks to Manuela
2026    Friedrich.)
2027
2028  Changes to documentation and commentary
2029
2030    theory.html now outlines tzdb's extensions to POSIX's model for
2031    civil time, and has a section "POSIX features no longer needed"
2032    that lists POSIX API components that are now vestigial.
2033    (From suggestions by Steve Summit.)  It also better distinguishes
2034    time zones from tz regions.  (From a suggestion by Guy Harris.)
2035
2036    Commentary is now more consistent about using the phrase "daylight
2037    saving time", to match the C name tm_isdst.  Daylight saving time
2038    need not occur in summer, and need not have a positive offset from
2039    standard time.
2040
2041    Commentary about historical transitions in Uruguay has been expanded
2042    with links to many relevant legal documents.
2043    (Thanks to Tim Parenti.)
2044
2045    Commentary now uses some non-ASCII characters with Unicode value
2046    less than U+0100, as they can be useful and should work even with
2047    older editors such as XEmacs.
2048
2049
2050Release 2018c - 2018-01-22 23:00:44 -0800
2051
2052  Briefly:
2053  Revert Irish changes that relied on negative SAVE values.
2054
2055  Changes to tm_isdst
2056
2057    Revert the 2018a change to Europe/Dublin.  As before, this change
2058    does not affect UT offsets or abbreviations; it affects only
2059    whether timestamps are considered to be standard time or
2060    daylight-saving time, as expressed in the tm_isdst flag of C's
2061    struct tm type.  This reversion is intended to be a temporary
2062    workaround for problems discovered with downstream uses of
2063    releases 2018a and 2018b, which implemented Irish time by using
2064    negative SAVE values in the Eire rules of the 'europe' file.
2065    Although negative SAVE values have been part of tzcode for many
2066    years and are supported by many platforms, they were not
2067    documented before 2018a and ICU and OpenJDK do not currently
2068    support them.  A mechanism to export data to platforms lacking
2069    support for negative DST is planned to be developed before the
2070    change is reapplied.  (Problems reported by Deborah Goldsmith and
2071    Stephen Colebourne.)
2072
2073  Changes to past timestamps
2074
2075    Japanese DST transitions (1948-1951) were Sundays at 00:00, not
2076    Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
2077
2078  Changes to build procedure
2079
2080    The build procedure now works around mawk 1.3.3's lack of support
2081    for character class expressions.  (Problem reported by Ohyama.)
2082
2083
2084Release 2018b - 2018-01-17 23:24:48 -0800
2085
2086  Briefly:
2087  Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
2088
2089  Changes to build procedure
2090
2091    The distribution now contains the file 'pacificnew' again.
2092    This file was inadvertently omitted in the 2018a distribution.
2093    (Problem reported by Matias Fonzo.)
2094
2095
2096Release 2018a - 2018-01-12 22:29:21 -0800
2097
2098  Briefly:
2099  São Tomé and Príncipe switched from +00 to +01.
2100  Brazil's DST will now start on November's first Sunday.
2101  Ireland's standard time is now in the summer, not the winter.
2102  Use Debian-style installation locations, instead of 4.3BSD-style.
2103  New zic option -t.
2104
2105  Changes to past and future timestamps
2106
2107    São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
2108    01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
2109
2110  Changes to future timestamps
2111
2112    Starting in 2018 southern Brazil will begin DST on November's
2113    first Sunday instead of October's third Sunday.  (Thanks to
2114    Steffen Thorsen.)
2115
2116  Changes to past timestamps
2117
2118    A discrepancy of 4 s in timestamps before 1931 in South Sudan has
2119    been corrected.  The 'backzone' and 'zone.tab' files did not agree
2120    with the 'africa' and 'zone1970.tab' files.  (Problem reported by
2121    Michael Deckers.)
2122
2123    The abbreviation invented for Bolivia Summer Time (1931-2) is now
2124    BST instead of BOST, to be more consistent with the convention
2125    used for Latvian Summer Time (1918-9) and for British Summer Time.
2126
2127  Changes to tm_isdst
2128
2129    Change Europe/Dublin so that it observes Irish Standard Time (UT
2130    +01) in summer and GMT (as negative daylight-saving) in winter,
2131    instead of observing standard time (GMT) in winter and Irish
2132    Summer Time (UT +01) in summer.  This change does not affect UT
2133    offsets or abbreviations; it affects only whether timestamps are
2134    considered to be standard time or daylight-saving time, as
2135    expressed in the tm_isdst flag of C's struct tm type.
2136    (Discrepancy noted by Derick Rethans.)
2137
2138  Changes to build procedure
2139
2140    The default installation locations have been changed to mostly
2141    match Debian circa 2017, instead of being designed as an add-on to
2142    4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
2143    TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
2144    USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
2145    locations more precisely.  (This responds to suggestions from
2146    Brian Inglis and from Steve Summit.)
2147
2148    The default installation procedure no longer creates the
2149    backward-compatibility link US/Pacific-New, which causes
2150    confusion during user setup (e.g., see Debian bug 815200).
2151    Use 'make BACKWARD="backward pacificnew"' to create the link
2152    anyway, for now.  Eventually we plan to remove the link entirely.
2153
2154    tzdata.zi now contains a version-number comment.
2155    (Suggested by Tom Lane.)
2156
2157    The Makefile now quotes values like BACKWARD more carefully when
2158    passing them to the shell.  (Problem reported by Zefram.)
2159
2160    Builders no longer need to specify -DHAVE_SNPRINTF on platforms
2161    that have snprintf and use pre-C99 compilers.  (Problem reported
2162    by Jon Skeet.)
2163
2164  Changes to code
2165
2166    zic has a new option -t FILE that specifies the location of the
2167    file that determines local time when TZ is unset.  The default for
2168    this location can be configured via the new TZDEFAULT makefile
2169    macro, which defaults to /etc/localtime.
2170
2171    Diagnostics and commentary now distinguish UT from UTC more
2172    carefully; see theory.html for more information about UT vs UTC.
2173
2174    zic has been ported to GCC 8's -Wstringop-truncation option.
2175    (Problem reported by Martin Sebor.)
2176
2177  Changes to documentation and commentary
2178
2179    The zic man page now documents the longstanding behavior that
2180    times and years can be out of the usual range, with negative times
2181    counting backwards from midnight and with year 0 preceding year 1.
2182    (Problem reported by Michael Deckers.)
2183
2184    The theory.html file now mentions the POSIX limit of six chars
2185    per abbreviation, and lists alphabetic abbreviations used.
2186
2187    The files tz-art.htm and tz-link.htm have been renamed to
2188    tz-art.html and tz-link.html, respectively, for consistency with
2189    other file names and to simplify web server configuration.
2190
2191
2192Release 2017c - 2017-10-20 14:49:34 -0700
2193
2194  Briefly:
2195  Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
2196  Fiji ends DST 2018-01-14, not 2018-01-21.
2197  Namibia switches from +01/+02 to +02 on 2018-04-01.
2198  Sudan switches from +03 to +02 on 2017-11-01.
2199  Tonga likely switches from +13/+14 to +13 on 2017-11-05.
2200  Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
2201  A new file tzdata.zi now holds a small text copy of all data.
2202  The zic input format has been regularized slightly.
2203
2204  Changes to future timestamps
2205
2206    Northern Cyprus has decided to resume EU rules starting
2207    2017-10-29, thus reinstituting winter time.
2208
2209    Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
2210    predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
2211    accordingly.
2212
2213    Namibia will switch from +01 with DST to +02 all year on
2214    2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
2215    at 02:00.  (Thanks to Steffen Thorsen.)
2216
2217    Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
2218    Atyya and Yahia Abdalla.)  South Sudan is not switching, so
2219    Africa/Juba is no longer a link to Africa/Khartoum.
2220
2221    Tonga has likely ended its experiment with DST, and will not
2222    adjust its clocks on 2017-11-05.  Although Tonga has not announced
2223    whether it will continue to observe DST, the IATA is assuming that
2224    it will not.  (Thanks to David Wade.)
2225
2226    Turks & Caicos will switch from -04 all year to -05 with US DST on
2227    2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
2228    at 02:00.  (Thanks to Steffen Thorsen.)
2229
2230  Changes to past timestamps
2231
2232    Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
2233    (Thanks to Arthur David Olson.)
2234
2235    Detroit did not observe DST in 1967.
2236
2237    Use railway time for Asia/Kolkata before 1941, by switching to
2238    Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
2239    1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
2240
2241    Europe/Dublin's 1946 and 1947 fallback transitions occurred at
2242    02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
2243
2244    Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
2245    American time in 1892, not 1879.  (Thanks to Michael Deckers.)
2246
2247    Adjust the 1867 transition in Alaska to better reflect the
2248    historical record, by changing it to occur on 1867-10-18 at 15:30
2249    Sitka time rather than at the start of 1867-10-17 local time.
2250    Although strictly speaking this is accurate only for Sitka,
2251    the rest of Alaska's blanks need to be filled in somehow.
2252
2253    Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
2254    (Thanks to Michael Deckers.)
2255
2256    Add 7 s to the UT offset in Asia/Yangon before 1920.
2257
2258  Changes to zone names
2259
2260    Remove Canada/East-Saskatchewan from the 'backward' file, as it
2261    exceeded the 14-character limit and was an unused misnomer anyway.
2262
2263  Changes to build procedure
2264
2265    To support applications that prefer to read time zone data in text
2266    form, two zic input files tzdata.zi and leapseconds are now
2267    installed by default.  The commands 'zic tzdata.zi' and 'zic -L
2268    leapseconds tzdata.zi' can reproduce the tzdata binary files
2269    without and with leap seconds, respectively.  To prevent these two
2270    new files from being installed, use 'make TZDATA_TEXT=', and to
2271    suppress leap seconds from the tzdata text installation, use 'make
2272    TZDATA_TEXT=tzdata.zi'.
2273
2274    'make BACKWARD=' now suppresses backward-compatibility names
2275    like 'US/Pacific' that are defined in the 'backward' and
2276    'pacificnew' files.
2277
2278    'make check' now works on systems that lack a UTF-8 locale,
2279    or that lack the nsgmls program.  Set UTF8_LOCALE to configure
2280    the name of a UTF-8 locale, if you have one.
2281
2282    Y2K runtime checks are no longer enabled by default.  Add
2283    -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
2284    adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
2285    to disable them.  (New name suggested by Brian Inglis.)
2286
2287    The build procedure for zdump now works on AIX 7.1.
2288    (Problem reported by Kees Dekker.)
2289
2290  Changes to code
2291
2292    zic and the reference runtime now reject multiple leap seconds
2293    within 28 days of each other, or leap seconds before the Epoch.
2294    As a result, support for double leap seconds, which was
2295    obsolescent and undocumented, has been removed.  Double leap
2296    seconds were an error in the C89 standard; they have never existed
2297    in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
2298    noticing glitches in the code that uncovered this problem.)
2299
2300    zic now warns about use of the obsolescent and undocumented -y
2301    option, and about use of the obsolescent TYPE field of Rule lines.
2302
2303    zic now allows unambiguous abbreviations like "Sa" and "Su" for
2304    weekdays; formerly it rejected them due to a bug.  Conversely, zic
2305    no longer considers non-prefixes to be abbreviations; for example,
2306    it no longer accepts "lF" as an abbreviation for "lastFriday".
2307    Also, zic warns about the undocumented usage with a "last-"
2308    prefix, e.g., "last-Fri".
2309
2310    Similarly, zic now accepts the unambiguous abbreviation "L" for
2311    "Link" in ordinary context and for "Leap" in leap-second context.
2312    Conversely, zic no longer accepts non-prefixes such as "La" as
2313    abbreviations for words like "Leap".
2314
2315    zic no longer accepts leap second lines in ordinary input, or
2316    ordinary lines in leap second input.  Formerly, zic sometimes
2317    warned about this undocumented usage and handled it incorrectly.
2318
2319    The new macro HAVE_TZNAME governs whether the tzname external
2320    variable is exported, instead of USG_COMPAT.  USG_COMPAT now
2321    governs only the external variables "timezone" and "daylight".
2322    This change is needed because the three variables are not in the
2323    same category: although POSIX requires tzname, it specifies the
2324    other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
2325    if not defined, the code attempts to guess it from other macros.
2326
2327    localtime.c and difftime.c no longer require stdio.h, and .c files
2328    other than zic.c no longer require sys/wait.h.
2329
2330    zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
2331
2332    Calculation of time_t extrema works around a bug in GCC 4.8.4
2333    (Reported by Stan Shebs and Joseph Myers.)
2334
2335    zic.c no longer mistranslates formats of line numbers in non-English
2336    locales.  (Problem reported by Benno Schulenberg.)
2337
2338    Several minor changes have been made to the code to make it a
2339    bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
2340    Dekker for reporting the problems.)
2341
2342  Changes to documentation and commentary
2343
2344    The two new files 'theory.html' and 'calendars' contain the
2345    contents of the removed file 'Theory'.  The goal is to document
2346    tzdb theory more accessibly.
2347
2348    The zic man page now documents abbreviation rules.
2349
2350    tz-link.htm now covers how to apply tzdata changes to clients.
2351    (Thanks to Jorge Fábregas for the AIX link.)  It also mentions MySQL.
2352
2353    The leap-seconds.list URL has been updated to something that is
2354    more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
2355
2356Release 2017b - 2017-03-17 07:30:38 -0700
2357
2358  Briefly: Haiti has resumed DST.
2359
2360  Changes to past and future timestamps
2361
2362    Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
2363
2364  Changes to past timestamps
2365
2366    Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
2367
2368    Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
2369    is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
2370
2371  Changes to code
2372
2373    The reference localtime implementation now falls back on the
2374    current US daylight-saving transition rules rather than the
2375    1987-2006 rules.  This fallback occurs only when (1) the TZ
2376    environment variable has a value like "AST4ADT" that asks
2377    for daylight saving time but does not specify the rules, (2) there
2378    is no file by that name, and (3) the TZDEFRULES file cannot be
2379    loaded.  (Thanks to Tom Lane.)
2380
2381
2382Release 2017a - 2017-02-28 00:05:36 -0800
2383
2384  Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
2385  discontinues DST.
2386
2387  Changes to future timestamps
2388
2389    Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
2390
2391    Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
2392    Its clocks diverge from America/Santiago starting 2017-05-13 at
2393    23:00, hiving off a new zone America/Punta_Arenas.  Although the
2394    Chilean government says this change expires in May 2019, for now
2395    assume it's permanent.  (Thanks to Juan Correa and Deborah
2396    Goldsmith.)  This also affects Antarctica/Palmer.
2397
2398  Changes to past timestamps
2399
2400    Fix many entries for historical timestamps for Europe/Madrid
2401    before 1979, to agree with tables compiled by Pere Planesas of the
2402    National Astronomical Observatory of Spain.  As a side effect,
2403    this changes some timestamps for Africa/Ceuta before 1929, which
2404    are probably guesswork anyway.  (Thanks to Steve Allen and
2405    Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
2406    correcting the 1901 transition.)
2407
2408    Ecuador observed DST from 1992-11-28 to 1993-02-05.
2409    (Thanks to Alois Treindl.)
2410
2411    Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
2412    (Thanks to Stepan Golosunov.)
2413
2414  Changes to past and future time zone abbreviations
2415
2416    Switch to numeric time zone abbreviations for South America, as
2417    part of the ongoing project of removing invented abbreviations.
2418    This avoids the need to invent an abbreviation for the new Chilean
2419    new zone.  Similarly, switch from invented to numeric time zone
2420    abbreviations for Afghanistan, American Samoa, the Azores,
2421    Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
2422    Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
2423    Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
2424    Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
2425    the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
2426    Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
2427    Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
2428    Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
2429    Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
2430    Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
2431    for half-hour daylight saving time in Belize before 1944 and in
2432    the Dominican Republic before 1975; and for Canary Islands before
2433    1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
2434    Indian Summer Time before 1942, for Indonesia before around 1964,
2435    for Kenya before 1960, for Liberia before 1973, for Madeira before
2436    1967, for Namibia before 1943, for the Netherlands in 1937-9, for
2437    Pakistan before 1971, for Western Sahara before 1977, and for
2438    Zaporozhye in 1880-1924.
2439
2440    For Alaska time from 1900 through 1967, instead of "CAT" use the
2441    abbreviation "AST", the abbreviation commonly used at the time
2442    (Atlantic Standard Time had not been standardized yet).  Use "AWT"
2443    and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
2444
2445    Use "CST" and "CDT" instead of invented abbreviations for Macau
2446    before 1999 and Taiwan before 1938, and use "JST" instead of the
2447    invented abbreviation "JCST" for Japan and Korea before 1938.
2448
2449  Change to database entry category
2450
2451    Move the Pacific/Johnston link from 'australasia' to 'backward',
2452    since Johnston is now uninhabited.
2453
2454  Changes to code
2455
2456    zic no longer mishandles some transitions in January 2038 when it
2457    attempts to work around Qt bug 53071.  This fixes a bug affecting
2458    Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
2459    now contains a workaround, useful when loading a file generated by
2460    a buggy zic.  (Problem and localtime.c fix reported by Bradley
2461    White.)
2462
2463    zdump -i now outputs non-hour numeric time zone abbreviations
2464    without a colon, e.g., "+0530" rather than "+05:30".  This agrees
2465    with zic %z and with common practice, and simplifies auditing of
2466    zdump output.
2467
2468    zdump is now buildable again with -DUSE_LTZ=0.
2469    (Problem reported by Joseph Myers.)
2470
2471    zdump.c now always includes private.h, to avoid code duplication
2472    with private.h.  (Problem reported by Kees Dekker.)
2473
2474    localtime.c no longer mishandles early or late timestamps
2475    when TZ is set to a POSIX-style string that specifies DST.
2476    (Problem reported by Kees Dekker.)
2477
2478    date and strftime now cause %z to generate "-0000" instead of
2479    "+0000" when the UT offset is zero and the time zone abbreviation
2480    begins with "-".
2481
2482  Changes to documentation and commentary
2483
2484    The 'Theory' file now better documents choice of historical time
2485    zone abbreviations.  (Problems reported by Michael Deckers.)
2486
2487    tz-link.htm now covers leap smearing, which is popular in clouds.
2488
2489
2490Release 2016j - 2016-11-22 23:17:13 -0800
2491
2492  Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
2493
2494  Changes to future timestamps
2495
2496    Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
2497    This hives off a new zone Europe/Saratov from Europe/Volgograd.
2498    (Thanks to Yuri Konotopov and Stepan Golosunov.)
2499
2500  Changes to past timestamps
2501
2502    The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
2503    Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
2504    1999, not fall 1994.  (Thanks to Stepan Golosunov.)
2505
2506  Changes to past time zone abbreviations
2507
2508    Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
2509    summer time before 1948.  The old use of "EET" was a typo.
2510
2511  Changes to code
2512
2513    zic no longer mishandles file systems that lack hard links, fixing
2514    bugs introduced in 2016g.  (Problems reported by Tom Lane.)
2515    Also, when the destination already contains symbolic links, zic
2516    should now work better on systems where the 'link' system call
2517    does not follow symbolic links.
2518
2519  Changes to documentation and commentary
2520
2521    tz-link.htm now documents the relationship between release version
2522    numbers and development-repository commit tags.  (Suggested by
2523    Paul Koning.)
2524
2525    The 'Theory' file now documents UT.
2526
2527    iso3166.tab now accents "Curaçao", and commentary now mentions
2528    the names "Cabo Verde" and "Czechia".  (Thanks to Jiří Boháč.)
2529
2530
2531Release 2016i - 2016-11-01 23:19:52 -0700
2532
2533  Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
2534  reintroduces DST on 2016-11-06.
2535
2536  Changes to future timestamps
2537
2538    Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
2539    2017-01-15 at 03:00.  Assume future observances in Tonga will be
2540    from the first Sunday in November through the third Sunday in
2541    January, like Fiji.  (Thanks to Pulu ʻAnau.)  Switch to numeric
2542    time zone abbreviations for this zone.
2543
2544  Changes to past and future timestamps
2545
2546    Northern Cyprus is now +03 year round, causing a split in Cyprus
2547    time zones starting 2016-10-30 at 04:00.  This creates a zone
2548    Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
2549
2550    Antarctica/Casey switched from +08 to +11 on 2016-10-22.
2551    (Thanks to Steffen Thorsen.)
2552
2553  Changes to past timestamps
2554
2555    Several corrections were made for pre-1975 timestamps in Italy.
2556    These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
2557    Europe/Vatican.
2558
2559    First, the 1893-11-01 00:00 transition in Italy used the new UT
2560    offset (+01), not the old (+00:49:56).  (Thanks to Michael
2561    Deckers.)
2562
2563    Second, rules for daylight saving in Italy were changed to agree
2564    with Italy's National Institute of Metrological Research (INRiM)
2565    except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
2566    Inglis, and Michael Deckers):
2567
2568      The 1916-06-03 transition was at 24:00, not 00:00.
2569
2570      The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
2571      00:00, not 01:00.
2572
2573      The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
2574      01:00.
2575
2576      The 1944-09-17 transition was at 03:00, not 01:00.  This
2577      particular change is taken from Italian law as INRiM's table,
2578      (which says 02:00) appears to have a typo here.  Also, keep the
2579      1944-04-03 transition for Europe/Rome, as Rome was controlled by
2580      Germany then.
2581
2582      The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
2583      not 00:00.
2584
2585  Changes to code
2586
2587    The code should now be buildable on AmigaOS merely by setting the
2588    appropriate Makefile variables.  (From a patch by Carsten Larsen.)
2589
2590
2591Release 2016h - 2016-10-19 23:17:57 -0700
2592
2593  Changes to future timestamps
2594
2595    Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
2596    2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
2597    future fall transitions will be on the last Saturday of October
2598    at 01:00, which is consistent with predicted spring transitions
2599    on the last Saturday of March.  (Thanks to Tim Parenti.)
2600
2601  Changes to past timestamps
2602
2603    In Turkey, transitions in 1986-1990 were at 01:00 standard time
2604    not at 02:00, and the spring 1994 transition was on March 20, not
2605    March 27.  (Thanks to Kıvanç Yazan.)
2606
2607  Changes to past and future time zone abbreviations
2608
2609    Asia/Colombo now uses numeric time zone abbreviations like "+0530"
2610    instead of alphabetic ones like "IST" and "LKT".  Various
2611    English-language sources use "IST", "LKT" and "SLST", with no
2612    working consensus.  (Usage of "SLST" mentioned by Sadika
2613    Sumanapala.)
2614
2615  Changes to code
2616
2617    zic no longer mishandles relativizing file names when creating
2618    symbolic links like /etc/localtime, when these symbolic links
2619    are outside the usual directory hierarchy.  This fixes a bug
2620    introduced in 2016g.  (Problem reported by Andreas Stieger.)
2621
2622  Changes to build procedure
2623
2624    New rules 'traditional_tarballs' and 'traditional_signatures' for
2625    building just the traditional-format distribution.  (Requested by
2626    Deborah Goldsmith.)
2627
2628    The file 'version' is now put into the tzdata tarball too.
2629    (Requested by Howard Hinnant.)
2630
2631  Changes to documentation and commentary
2632
2633    The 'Theory' file now has a section on interface stability.
2634    (Requested by Paul Koning.)  It also mentions features like
2635    tm_zone and localtime_rz that have long been supported by the
2636    reference code.
2637
2638    tz-link.htm has improved coverage of time zone boundaries suitable
2639    for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
2640    Johnson.)
2641
2642    The US commentary now mentions Allen and the "day of two noons".
2643
2644    The Fiji commentary mentions the government's 2016-10-03 press
2645    release.  (Thanks to Raymond Kumar.)
2646
2647
2648Release 2016g - 2016-09-13 08:56:38 -0700
2649
2650  Changes to future timestamps
2651
2652    Turkey switched from EET/EEST (+02/+03) to permanent +03,
2653    effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
2654    than an invented abbreviation for the new time.
2655
2656    New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
2657    (Thanks to Tim Parenti.)
2658
2659  Changes to past timestamps
2660
2661    For America/Los_Angeles, spring-forward transition times have been
2662    corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
2663    1950-1966.
2664
2665    For zones using Soviet time on 1919-07-01, transitions to UT-based
2666    time were at 00:00 UT, not at 02:00 local time.  The affected
2667    zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
2668    Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
2669
2670  Changes to past and future time zone abbreviations
2671
2672    The Factory zone now uses the time zone abbreviation -00 instead
2673    of a long English-language string, as -00 is now the normal way to
2674    represent an undefined time zone.
2675
2676    Several zones in Antarctica and the former Soviet Union, along
2677    with zones intended for ships at sea that cannot use POSIX TZ
2678    strings, now use numeric time zone abbreviations instead of
2679    invented or obsolete alphanumeric abbreviations.  The affected
2680    zones are Antarctica/Casey, Antarctica/Davis,
2681    Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
2682    Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
2683    Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
2684    Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
2685    Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
2686    Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
2687    Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
2688    Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
2689    Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
2690    Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
2691    Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
2692    Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
2693    Europe/Minsk, Europe/Samara, Europe/Volgograd, and
2694    Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
2695    was replaced by +05, whereas MSK and MSD were kept as they are not
2696    our invention and are widely used.
2697
2698  Changes to zone names
2699
2700    Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
2701    (Thanks to David Massoud.)
2702
2703  Changes to code
2704
2705    zic no longer generates binary files containing POSIX TZ-like
2706    strings that disagree with the local time type after the last
2707    explicit transition in the data.  This fixes a bug with
2708    Africa/Casablanca and Africa/El_Aaiun in some year-2037 timestamps
2709    on the reference platform.  (Thanks to Alexander Belopolsky for
2710    reporting the bug and suggesting a way forward.)
2711
2712    If the installed localtime and/or posixrules files are symbolic
2713    links, zic now keeps them symbolic links when updating them, for
2714    compatibility with platforms like OpenSUSE where other programs
2715    configure these files as symlinks.
2716
2717    zic now avoids hard linking to symbolic links, avoids some
2718    unnecessary mkdir and stat system calls, and uses shorter file
2719    names internally.
2720
2721    zdump has a new -i option to generate transitions in a
2722    smaller but still human-readable format.  This option is
2723    experimental, and the output format may change in future versions.
2724    (Thanks to Jon Skeet for suggesting that an option was needed,
2725    and thanks to Tim Parenti and Chris Rovick for further comments.)
2726
2727  Changes to build procedure
2728
2729    An experimental distribution format is available, in addition
2730    to the traditional format which will continue to be distributed.
2731    The new format is a tarball tzdb-VERSION.tar.lz with signature
2732    file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
2733    tzdb-VERSION containing the code and data of the traditional
2734    two-tarball format, along with extra data that may be useful.
2735    (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
2736    for comments about the experimental format.)
2737
2738    The release version number is now more accurate in the usual case
2739    where releases are built from a Git repository.  For example, if
2740    23 commits and some working-file changes have been made since
2741    release 2016g, the version number is now something like
2742    '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
2743    Tagged releases use the same version number format as before,
2744    e.g., '2016g'.  To support the more accurate version number, its
2745    specification has moved from a line in the Makefile to a new
2746    source file 'version'.
2747
2748    The experimental distribution contains a file to2050.tzs that
2749    contains what should be the output of 'zdump -i -c 2050' on
2750    primary zones.  If this file is available, 'make check' now checks
2751    that zdump generates this output.
2752
2753    'make check_web' now works on Fedora-like distributions.
2754
2755  Changes to documentation and commentary
2756
2757    tzfile.5 now documents the new restriction on POSIX TZ-like
2758    strings that is now implemented by zic.
2759
2760    Comments now cite URLs for some 1917-1921 Russian DST decrees.
2761    (Thanks to Alexander Belopolsky.)
2762
2763    tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
2764    (thanks to Meno Hochschild) and ThreeTen-Extra, and its
2765    description of Java 8 has been brought up to date (thanks to
2766    Stephen Colebourne).  Its description of local time on Mars has
2767    been updated to match current practice, and URLs have been updated
2768    and some obsolete ones removed.
2769
2770
2771Release 2016f - 2016-07-05 16:26:51 +0200
2772
2773  Changes affecting future timestamps
2774
2775    The Egyptian government changed its mind on short notice, and
2776    Africa/Cairo will not introduce DST starting 2016-07-07 after all.
2777    (Thanks to Mina Samuel.)
2778
2779    Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
2780    (Thanks to Stepan Golosunov.)
2781
2782  Changes to past and future timestamps
2783
2784    Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
2785    abbreviations instead of invented ones.
2786
2787  Changes affecting past timestamps
2788
2789    Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
2790    (Thanks to Stepan Golosunov.)
2791
2792
2793Release 2016e - 2016-06-14 08:46:16 -0700
2794
2795  Changes affecting future timestamps
2796
2797    Africa/Cairo observes DST in 2016 from July 7 to the end of October.
2798    Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
2799    For future years, guess April's last Thursday to October's last
2800    Thursday except for Ramadan.
2801
2802  Changes affecting past timestamps
2803
2804    Locations while uninhabited now use '-00', not 'zzz', as a
2805    placeholder time zone abbreviation.  This is inspired by Internet
2806    RFC 3339 and is more consistent with numeric time zone
2807    abbreviations already used elsewhere.  The change affects several
2808    arctic and antarctic locations, e.g., America/Cambridge_Bay before
2809    1920 and Antarctica/Troll before 2005.
2810
2811    Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
2812    at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
2813
2814  Changes to code
2815
2816    zic now outputs a dummy transition at time 2**31 - 1 in zones
2817    whose POSIX-style TZ strings contain a '<'.  This mostly works
2818    around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
2819    (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
2820
2821  Changes affecting documentation and commentary
2822
2823    tz-link.htm says why governments should give plenty of notice for
2824    time zone or DST changes, and refers to Matt Johnson's blog post.
2825
2826    tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
2827
2828
2829Release 2016d - 2016-04-17 22:50:29 -0700
2830
2831  Changes affecting future timestamps
2832
2833    America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
2834    (Thanks to Alexander Krivenyshev for the heads-up.)
2835
2836    Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
2837    (Thanks to Alexander Krivenyshev and Matt Johnson.)
2838
2839    New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
2840    Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
2841    at 02:00.  (Thanks to Stepan Golosunov.)
2842
2843  Changes affecting past timestamps
2844
2845    New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
2846    Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
2847    1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
2848    the same change.  (Thanks to Stepan Golosunov.)
2849
2850    Russia and nearby locations had daylight-saving transitions on
2851    1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
2852    1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
2853    Golosunov.)
2854
2855    Many corrections to historical time in Kazakhstan from 1991
2856    through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
2857    invented time zone abbreviations with numeric abbreviations.
2858
2859  Changes to commentary
2860
2861    Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
2862
2863
2864Release 2016c - 2016-03-23 00:51:27 -0700
2865
2866  Changes affecting future timestamps
2867
2868    Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
2869
2870    Chile reverts from permanent to seasonal DST.  (Thanks to Juan
2871    Correa for the heads-up, and to Tim Parenti for corrections.)
2872    Guess that future transitions are August's and May's second
2873    Saturdays at 24:00 mainland time.  Also, call the period from
2874    2014-09-07 through 2016-05-14 daylight saving time instead of
2875    standard time, as that seems more appropriate now.
2876
2877  Changes affecting past timestamps
2878
2879    Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
2880    +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
2881    from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
2882    (Thanks to Stepan Golosunov.)
2883
2884  Changes to commentary
2885
2886    Several updates and URLs for historical and proposed Russian changes.
2887    (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
2888
2889
2890Release 2016b - 2016-03-12 17:30:14 -0800
2891
2892  Compatibility note
2893
2894    Starting with release 2016b, some data entries cause zic implementations
2895    derived from tz releases 2005j through 2015e to issue warnings like
2896    "time zone abbreviation differs from POSIX standard (+03)".
2897    These warnings should not otherwise affect zic's output and can safely be
2898    ignored on today's platforms, as the warnings refer to a restriction in
2899    POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
2900    warnings is to upgrade to zic derived from tz releases 2015f and later.
2901
2902  Changes affecting future timestamps
2903
2904    New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
2905    Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
2906    2016-03-27 at 02:00 local time.  They need distinct zones since their
2907    post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
2908    Altai Republic, Russia, which will switch from +06 to +07 on the same date
2909    and local time.  The Astrakhan change is already official; the others have
2910    passed the first reading in the State Duma and are extremely likely.
2911    Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
2912    (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
2913    and Stepan Golosunov for followup.)
2914
2915    As a trial of a new system that needs less information to be made up,
2916    the new zones use numeric time zone abbreviations like "+04"
2917    instead of invented abbreviations like "ASTT".
2918
2919    Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
2920    Steffen Thorsen.)
2921
2922    Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
2923    (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
2924    Saturday at 01:00, not March's last Friday at 24:00.
2925
2926  Changes affecting past timestamps
2927
2928    Europe/Chisinau observed DST during 1990, and switched from +04 to
2929    +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
2930    (Thanks to Stepan Golosunov.)
2931
2932    1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
2933    KUYT/KUYST.  (Thanks to Stepan Golosunov.)
2934
2935  Changes to code
2936
2937    tzselect's diagnostics and checking, and checktab.awk's checking,
2938    have been improved.  (Thanks to J William Piggott.)
2939
2940    tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
2941
2942    tzselect now tests Julian-date TZ settings more accurately.
2943    (Thanks to J William Piggott.)
2944
2945  Changes to commentary
2946
2947    Comments in zone tables have been improved.  (Thanks to J William Piggott.)
2948
2949    tzselect again limits its menu comments so that menus fit on a
2950    24×80 alphanumeric display.
2951
2952    A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
2953
2954    In the Theory file, the description of possible time zone abbreviations in
2955    tzdata has been cleaned up, as the old description was unclear and
2956    inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
2957
2958
2959Release 2016a - 2016-01-26 23:28:02 -0800
2960
2961  Changes affecting future timestamps
2962
2963    America/Cayman will not observe daylight saving this year after all.
2964    Revert our guess that it would.  (Thanks to Matt Johnson.)
2965
2966    Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
2967    (Thanks to Alexander Krivenyshev.)
2968
2969    Asia/Tehran now has DST predictions for the year 2038 and later,
2970    to be March 21 00:00 to September 21 00:00.  This is likely better
2971    than predicting no DST, albeit off by a day every now and then.
2972
2973  Changes affecting past and future timestamps
2974
2975    America/Metlakatla switched from PST all year to AKST/AKDT on
2976    2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
2977
2978    America/Santa_Isabel has been removed, and replaced with a
2979    backward compatibility link to America/Tijuana.  Its contents were
2980    apparently based on a misreading of Mexican legislation.
2981
2982  Changes affecting past timestamps
2983
2984    Asia/Karachi's two transition times in 2002 were off by a minute.
2985    (Thanks to Matt Johnson.)
2986
2987  Changes affecting build procedure
2988
2989    An installer can now combine leap seconds with use of the backzone file,
2990    e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
2991    The old 'make posix_packrat' rule is now marked as obsolescent.
2992    (Thanks to Ian Abbott for an initial implementation.)
2993
2994  Changes affecting documentation and commentary
2995
2996    A new file LICENSE makes it easier to see that the code and data
2997    are mostly public-domain.  (Thanks to James Knight.)  The three
2998    non-public-domain files now use the current (3-clause) BSD license
2999    instead of older versions of that license.
3000
3001    tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
3002    CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
3003    on editing tz source files (with a mention of Sublime zoneinfo,
3004    thanks to Gilmore Davidson).
3005
3006    The Theory and asia files now mention the 2015 book "The Global
3007    Transformation of Time, 1870-1950", and cite a couple of reviews.
3008
3009    The America/Chicago entry now documents the informal use of US
3010    central time in Fort Pierre, South Dakota.  (Thanks to Rick
3011    McDermid, Matt Johnson, and Steve Jones.)
3012
3013
3014Release 2015g - 2015-10-01 00:39:51 -0700
3015
3016  Changes affecting future timestamps
3017
3018    Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
3019    (Thanks to Fatih.)
3020
3021    Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
3022    (Thanks to Alexander Krivenyshev.)
3023
3024    Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
3025    (Thanks to Ken Rylander.)
3026
3027    Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
3028    effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
3029    New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
3030
3031  Changes affecting past timestamps
3032
3033    Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
3034
3035  Changes affecting code
3036
3037    localtime no longer mishandles America/Anchorage after 2037.
3038    (Thanks to Bradley White for reporting the bug.)
3039
3040    On hosts with signed 32-bit time_t, localtime no longer mishandles
3041    Pacific/Fiji after 2038-01-16 14:00 UTC.
3042
3043    The localtime module allows the variables 'timezone', 'daylight',
3044    and 'altzone' to be in common storage shared with other modules,
3045    and declares them in case the system <time.h> does not.
3046    (Problems reported by Kees Dekker.)
3047
3048    On platforms with tm_zone, strftime.c now assumes it is not NULL.
3049    This simplifies the code and is consistent with zdump.c.
3050    (Problem reported by Christos Zoulas.)
3051
3052  Changes affecting documentation
3053
3054   The tzfile man page now documents that transition times denote the
3055   starts (not the ends) of the corresponding time periods.
3056   (Ambiguity reported by Bill Seymour.)
3057
3058
3059Release 2015f - 2015-08-10 18:06:56 -0700
3060
3061  Changes affecting future timestamps
3062
3063    North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
3064    The abbreviation remains "KST".  (Thanks to Robert Elz.)
3065
3066    Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
3067    and Pablo Camargo.)
3068
3069  Changes affecting past and future timestamps
3070
3071    Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
3072    (Thanks to Roman Tudos.)
3073
3074  Changes affecting data format and code
3075
3076    zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
3077    field of a Rule line should now be '-'; the old values 'even',
3078    'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
3079    Although the implementation has not changed, these features do not
3080    work in the default installation, they are not used in the data,
3081    and they are now considered obsolescent.
3082
3083    zic now checks that two rules don't take effect at the same time.
3084    (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
3085    simultaneity are now documented.
3086
3087    The two characters '%z' in a zone format now stand for the UT
3088    offset, e.g., '-07' for seven hours behind UT and '+0530' for
3089    five hours and thirty minutes ahead.  This better supports time
3090    zone abbreviations conforming to POSIX.1-2001 and later.
3091
3092  Changes affecting installed data files
3093
3094    Comments for America/Halifax and America/Glace_Bay have been improved.
3095    (Thanks to Brian Inglis.)
3096
3097    Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
3098    Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
3099    installed data files for Europe/Simferopol and Europe/Tallinn.
3100    It does not affect timestamps.  (Thanks to Howard Hinnant.)
3101
3102  Changes affecting code
3103
3104    zdump and zic no longer warn about valid time zone abbreviations
3105    like '-05'.
3106
3107    Some Visual Studio 2013 warnings have been suppressed.
3108    (Thanks to Kees Dekker.)
3109
3110    'date' no longer sets the time of day and its -a, -d, -n and -t
3111    options have been removed.  Long obsolescent, the implementation
3112    of these features had porting problems.  Builders no longer need
3113    to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
3114    (Thanks to Kees Dekker for pointing out the problem.)
3115
3116  Changes affecting documentation
3117
3118    The Theory file mentions naming issues earlier, as these seem to be
3119    poorly publicized (thanks to Gilmore Davidson for reporting the problem).
3120
3121    tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
3122
3123    Mention that Herbert Samuel introduced the term "Summer Time".
3124
3125
3126Release 2015e - 2015-06-13 10:56:02 -0700
3127
3128  Changes affecting future timestamps
3129
3130    Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
3131    not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
3132
3133    Assume Cayman Islands will observe DST starting next year, using US rules.
3134    Although it isn't guaranteed, it is the most likely.
3135
3136  Changes affecting data format
3137
3138    The file 'iso3166.tab' now uses UTF-8, so that its entries can better
3139    spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
3140
3141  Changes affecting code
3142
3143    When displaying data, tzselect converts it to the current locale's
3144    encoding if the iconv command works.  (Problem reported by random832.)
3145
3146    tzselect no longer mishandles Dominica, fixing a bug introduced
3147    in Release 2014f.  (Problem reported by Owen Leibman.)
3148
3149    zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
3150    This fixes a bug introduced in Release 2014f.
3151    (Problem reported by Leonardo Chiquitto.)
3152
3153
3154Release 2015d - 2015-04-24 08:09:46 -0700
3155
3156  Changes affecting future timestamps
3157
3158    Egypt will not observe DST in 2015 and will consider canceling it
3159    permanently.  For now, assume no DST indefinitely.
3160    (Thanks to Ahmed Nazmy and Tim Parenti.)
3161
3162  Changes affecting past timestamps
3163
3164    America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
3165    1966-07-01.  Also, Yukon's time zone history is documented better.
3166    (Thanks to Brian Inglis and Dennis Ferguson.)
3167
3168  Change affecting past and future time zone abbreviations
3169
3170    The abbreviations for Hawaii-Aleutian standard and daylight times
3171    have been changed from HAST/HADT to HST/HDT, as per US Government
3172    Printing Office style.  This affects only America/Adak since 1983,
3173    as America/Honolulu was already using the new style.
3174
3175  Changes affecting code
3176
3177   zic has some minor performance improvements.
3178
3179
3180Release 2015c - 2015-04-11 08:55:55 -0700
3181
3182  Changes affecting future timestamps
3183
3184    Egypt's spring-forward transition is at 24:00 on April's last Thursday,
3185    not 00:00 on April's last Friday.  2015's transition will therefore be on
3186    Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
3187    apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
3188
3189  Changes affecting past timestamps
3190
3191    The following changes affect some pre-1991 Chile-related timestamps
3192    in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
3193
3194      The 1910 transition was January 10, not January 1.
3195
3196      The 1918 transition was September 10, not September 1.
3197
3198      The UT -04 time observed from 1932 to 1942 is now considered to
3199      be standard time, not year-round DST.
3200
3201      Santiago observed DST (UT -03) from 1946-07-15 through
3202      1946-08-31, then reverted to standard time, then switched to -05
3203      on 1947-04-01.
3204
3205      Assume transitions before 1968 were at 00:00, since we have no data
3206      saying otherwise.
3207
3208      The spring 1988 transition was 1988-10-09, not 1988-10-02.
3209      The fall 1990 transition was 1990-03-11, not 1990-03-18.
3210
3211      Assume no UT offset change for Pacific/Easter on 1890-01-01,
3212      and omit all transitions on Pacific/Easter from 1942 through 1946
3213      since we have no data suggesting that they existed.
3214
3215    One more zone has been turned into a link, as it differed
3216    from an existing zone only for older timestamps.  As usual,
3217    this change affects UT offsets in pre-1970 timestamps only.
3218    The zone's old contents have been moved to the 'backzone' file.
3219    The affected zone is America/Montreal.
3220
3221  Changes affecting commentary
3222
3223    Mention the TZUpdater tool.
3224
3225    Mention "The Time Now".  (Thanks to Brandon Ramsey.)
3226
3227
3228Release 2015b - 2015-03-19 23:28:11 -0700
3229
3230  Changes affecting future timestamps
3231
3232    Mongolia will start observing DST again this year, from the last
3233    Saturday in March at 02:00 to the last Saturday in September at 00:00.
3234    (Thanks to Ganbold Tsagaankhuu.)
3235
3236    Palestine will start DST on March 28, not March 27.  Also,
3237    correct the fall 2014 transition from September 26 to October 24.
3238    Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
3239
3240  Changes affecting past timestamps
3241
3242    The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
3243    regression.  (Thanks to Stuart Bishop for reporting the problem.)
3244
3245    Some more zones have been turned into links, when they differed
3246    from existing zones only for older timestamps.  As usual,
3247    these changes affect UT offsets in pre-1970 timestamps only.
3248    Their old contents have been moved to the 'backzone' file.
3249    The affected zones are: America/Antigua, America/Cayman,
3250    Pacific/Midway, and Pacific/Saipan.
3251
3252  Changes affecting time zone abbreviations
3253
3254    Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
3255    (Thanks to Hank W.)
3256
3257  Changes affecting code
3258
3259    Fix integer overflow bug in reference 'mktime' implementation.
3260    (Problem reported by Jörg Richter.)
3261
3262    Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
3263    to be used in the same executable as standard-library time_t functions.
3264    (Problems reported by Bradley White.)
3265
3266  Changes affecting commentary
3267
3268    Cite the recent Mexican decree changing Quintana Roo's time zone.
3269    (Thanks to Carlos Raúl Perasso.)
3270
3271    Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
3272
3273    Update info about Mars time.
3274
3275
3276Release 2015a - 2015-01-29 22:35:20 -0800
3277
3278  Changes affecting future timestamps
3279
3280    The Mexican state of Quintana Roo, represented by America/Cancun,
3281    will shift from Central Time with DST to Eastern Time without DST
3282    on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
3283
3284    Chile will not change clocks in April or thereafter; its new standard time
3285    will be its old daylight saving time.  This affects America/Santiago,
3286    Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
3287
3288    New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
3289    (Thanks to Tim Parenti.)
3290
3291  Changes affecting past timestamps
3292
3293    Iceland observed DST in 1919 and 1921, and its 1939 fallback
3294    transition was Oct. 29, not Nov. 29.  Remove incorrect data from
3295    Shanks about time in Iceland between 1837 and 1908.
3296
3297    Some more zones have been turned into links, when they differed
3298    from existing zones only for older timestamps.  As usual,
3299    these changes affect UT offsets in pre-1970 timestamps only.
3300    Their old contents have been moved to the 'backzone' file.
3301    The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
3302    and Asia/Muscat.
3303
3304  Changes affecting code
3305
3306    tzalloc now scrubs time zone abbreviations compatibly with the way
3307    that tzset always has, by replacing invalid bytes with '_' and by
3308    shortening too-long abbreviations.
3309
3310    tzselect ports to POSIX awk implementations, no longer mishandles
3311    POSIX TZ settings when GNU awk is used, and reports POSIX TZ
3312    settings to the user.  (Thanks to Stefan Kuhn.)
3313
3314  Changes affecting build procedure
3315
3316    'make check' now checks for links to links in the data.
3317    One such link (for Africa/Asmera) has been fixed.
3318    (Thanks to Stephen Colebourne for pointing out the problem.)
3319
3320  Changes affecting commentary
3321
3322    The leapseconds file commentary now mentions the expiration date.
3323    (Problem reported by Martin Burnicki.)
3324
3325    Update Mexican Library of Congress URL.
3326
3327
3328Release 2014j - 2014-11-10 17:37:11 -0800
3329
3330  Changes affecting current and future timestamps
3331
3332    Turks & Caicos' switch from US eastern time to UT -04 year-round
3333    did not occur on 2014-11-02 at 02:00.  It's currently scheduled
3334    for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
3335
3336  Changes affecting past timestamps
3337
3338    Many pre-1989 timestamps have been corrected for Asia/Seoul and
3339    Asia/Pyongyang, based on sources for the Korean-language Wikipedia
3340    entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
3341    longer guess that Pyongyang mimicked Seoul time after World War II,
3342    as this is politically implausible.
3343
3344    Some more zones have been turned into links, when they differed
3345    from existing zones only for older timestamps.  As usual,
3346    these changes affect UT offsets in pre-1970 timestamps only.
3347    Their old contents have been moved to the 'backzone' file.
3348    The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
3349    Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
3350    Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
3351    Indian/Mayotte.
3352
3353  Changes affecting commentary
3354
3355    The commentary is less enthusiastic about Shanks as a source,
3356    and is more careful to distinguish UT from UTC.
3357
3358
3359Release 2014i - 2014-10-21 22:04:57 -0700
3360
3361  Changes affecting future timestamps
3362
3363    Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
3364    (Thanks to Ken Rylander for the heads-up.)  Guess that future
3365    years will use a similar pattern.
3366
3367    A new Zone Pacific/Bougainville, for the part of Papua New Guinea
3368    that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
3369    (Thanks to Kiley Walbom for the heads-up.)
3370
3371  Changes affecting time zone abbreviations
3372
3373    Since Belarus is not changing its clocks even though Moscow is,
3374    the time zone abbreviation in Europe/Minsk is changing from FET
3375    to its more traditional value MSK on 2014-10-26 at 01:00.
3376    (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
3377
3378    The new abbreviation IDT stands for the pre-1976 use of UT +08 in
3379    Indochina, to distinguish it better from ICT (+07).
3380
3381  Changes affecting past timestamps
3382
3383    Many timestamps have been corrected for Asia/Ho_Chi_Minh before 1976
3384    (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
3385    authoritative book).  Asia/Ho_Chi_Minh has been added to
3386    zone1970.tab, to give tzselect users in Vietnam two choices,
3387    since north and south Vietnam disagreed after our 1970 cutoff.
3388
3389    Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
3390    they differed from existing zones only for older timestamps.  As
3391    usual, these changes affect pre-1970 timestamps only.  Their old
3392    contents have been moved to the 'backzone' file.
3393
3394  Changes affecting code
3395
3396    The time-related library functions now set errno on failure, and
3397    some crashes in the new tzalloc-related library functions have
3398    been fixed.  (Thanks to Christos Zoulas for reporting most of
3399    these problems and for suggesting fixes.)
3400
3401    If USG_COMPAT is defined and the requested timestamp is standard time,
3402    the tz library's localtime and mktime functions now set the extern
3403    variable timezone to a value appropriate for that timestamp; and
3404    similarly for ALTZONE, daylight saving time, and the altzone variable.
3405    This change is a companion to the tzname change in 2014h, and is
3406    designed to make timezone and altzone more compatible with tzname.
3407
3408    The tz library's functions now set errno to EOVERFLOW if they fail
3409    because the result cannot be represented.  ctime and ctime_r now
3410    return NULL and set errno when a timestamp is out of range, rather
3411    than having undefined behavior.
3412
3413    Some bugs associated with the new 2014g functions have been fixed.
3414    This includes a bug that largely incapacitated the new functions
3415    time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
3416    It also includes some uses of uninitialized variables after tzalloc.
3417    The new code uses the standard type 'ssize_t', which the Makefile
3418    now gives porting advice about.
3419
3420  Changes affecting commentary
3421
3422    Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
3423
3424
3425Release 2014h - 2014-09-25 18:59:03 -0700
3426
3427  Changes affecting past timestamps
3428
3429    America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
3430
3431    Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
3432    not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
3433
3434    Some more zones have been turned into links, when they differed
3435    from existing zones only for older timestamps.  As usual,
3436    these changes affect UT offsets in pre-1970 timestamps only.
3437    Their old contents have been moved to the 'backzone' file.
3438    The affected zones are: Africa/Blantyre, Africa/Bujumbura,
3439    Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
3440    Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
3441
3442  Changes affecting code
3443
3444    zdump -V and -v now output gmtoff= values on all platforms,
3445    not merely on platforms defining TM_GMTOFF.
3446
3447    The tz library's localtime and mktime functions now set tzname to a value
3448    appropriate for the requested timestamp, and zdump now uses this
3449    on platforms not defining TM_ZONE, fixing a 2014g regression.
3450    (Thanks to Tim Parenti for reporting the problem.)
3451
3452    The tz library no longer sets tzname if localtime or mktime fails.
3453
3454    zdump -c no longer mishandles transitions near year boundaries.
3455    (Thanks to Tim Parenti for reporting the problem.)
3456
3457    An access to uninitialized data has been fixed.
3458    (Thanks to Jörg Richter for reporting the problem.)
3459
3460    When THREAD_SAFE is defined, the code ports to the C11 memory model.
3461    A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
3462    and two threads race to initialize data used by gmtime-like functions.
3463    (Thanks to Andy Heninger for reporting the problems.)
3464
3465  Changes affecting build procedure
3466
3467    'make check' now checks better for properly sorted data.
3468
3469  Changes affecting documentation and commentary
3470
3471    zdump's gmtoff=N output is now documented, and its isdst=D output
3472    is now documented to possibly output D values other than 0 or 1.
3473
3474    zdump -c's treatment of years is now documented to use the
3475    Gregorian calendar and Universal Time without leap seconds,
3476    and its behavior at cutoff boundaries is now documented better.
3477    (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
3478
3479    Programs are now documented to use the proleptic Gregorian calendar.
3480    (Thanks to Alan Barrett for the suggestion.)
3481
3482    Fractional-second GMT offsets have been documented for civil time
3483    in 19th-century Chennai, Jakarta, and New York.
3484
3485
3486Release 2014g - 2014-08-28 12:31:23 -0700
3487
3488  Changes affecting future timestamps
3489
3490    Turks & Caicos is switching from US eastern time to UT -04
3491    year-round, modeled as a switch on 2014-11-02 at 02:00.
3492    [As noted in 2014j, this switch was later delayed.]
3493
3494  Changes affecting past timestamps
3495
3496    Time in Russia or the USSR before 1926 or so has been corrected by
3497    a few seconds in the following zones: Asia/Irkutsk,
3498    Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
3499    Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
3500    Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
3501    Vladimir Karpinsky.)
3502
3503    The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
3504    This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
3505    Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
3506    GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
3507    (Thanks to Stephen Colebourne for pointing to the decree.)
3508
3509    Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
3510
3511    A new file 'backzone' contains data which may appeal to
3512    connoisseurs of old timestamps, although it is out of scope for
3513    the tz database, is often poorly sourced, and contains some data
3514    that is known to be incorrect.  The new file is not recommended
3515    for ordinary use and its entries are not installed by default.
3516    (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
3517    Isle of Man entries.)
3518
3519    Some more zones have been turned into links, when they differed
3520    from existing zones only for older timestamps.  As usual,
3521    these changes affect UT offsets in pre-1970 timestamps only.
3522    Their old contents have been moved to the 'backzone' file.
3523    The affected zones are: Africa/Bangui, Africa/Brazzaville,
3524    Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
3525    Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
3526
3527  Changes affecting code
3528
3529    Unless NETBSD_INSPIRED is defined to 0, the tz library now
3530    supplies functions for creating and using objects that represent
3531    timezones. The new functions are tzalloc, tzfree, localtime_rz,
3532    mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
3533    time2posix_z.  They are intended for performance: for example,
3534    localtime_rz (unlike localtime_r) is trivially thread-safe without
3535    locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
3536    functions, and to Alan Barrett and Jonathan Lennox for helping to
3537    debug the change.)
3538
3539    zdump now builds with the tz library unless USE_LTZ is defined to 0,
3540    This lets zdump use tz features even if the system library lacks them.
3541    To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
3542    TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
3543
3544    zdump now uses localtime_rz if available, as it's significantly faster,
3545    and it can help zdump better diagnose invalid timezone names.
3546    Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
3547    defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
3548    not available, zdump now uses localtime_r and tzset if available,
3549    as this is a bit cleaner and faster than plain localtime.  Compile
3550    with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
3551    lacks these two functions.
3552
3553    If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
3554    Although not needed for tz's own applications, which are single-threaded,
3555    this supports POSIX better if the tz library is used in multithreaded apps.
3556
3557    Some crashes have been fixed when zdump or the tz library is given
3558    invalid or outlandish input.
3559
3560    The tz library no longer mishandles leap seconds on platforms with
3561    unsigned time_t in timezones that lack ordinary transitions after 1970.
3562
3563    The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
3564    already defined, to make it easier to configure on common platforms.
3565    Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
3566
3567    Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
3568    assumes that reading uninitialized memory yields garbage values
3569    but does not cause other problems such as traps.
3570
3571    If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
3572    more likely to guess right for ambiguous timestamps near
3573    transitions where tm_isdst does not change.
3574
3575    If HAVE_STRFTIME_L is defined to 1, the tz library now defines
3576    strftime_l for compatibility with recent versions of POSIX.
3577    Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
3578    to 1 on recent POSIX versions, and to 0 otherwise.
3579
3580    tzselect -c now uses a hybrid distance measure that works better
3581    in Africa.  (Thanks to Alan Barrett for noting the problem.)
3582
3583    The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
3584    or when time_tz is defined.
3585
3586    When HAVE_UTMPX_H is set the 'date' command now builds on systems
3587    whose <utmpx.h> file does not define WTMPX_FILE, and when setting
3588    the date it updates the wtmpx file if _PATH_WTMPX is defined.
3589    This affects GNU/Linux and similar systems.
3590
3591    For easier maintenance later, some C code has been simplified,
3592    some lint has been removed, and the code has been tweaked so that
3593    plain 'make' is more likely to work.
3594
3595    The C type 'bool' is now used for boolean values, instead of 'int'.
3596
3597    The long-obsolete LOCALE_HOME code has been removed.
3598
3599    The long-obsolete 'gtime' function has been removed.
3600
3601  Changes affecting build procedure
3602
3603    'zdump' no longer links in ialloc.o, as it's not needed.
3604
3605    'make check_time_t_alternatives' no longer assumes GNU diff.
3606
3607  Changes affecting distribution tarballs
3608
3609    The files checktab.awk and zoneinfo2tdf.pl are now distributed in
3610    the tzdata tarball instead of the tzcode tarball, since they help
3611    maintain the data.  The NEWS and Theory files are now also
3612    distributed in the tzdata tarball, as they're relevant for data.
3613    (Thanks to Alan Barrett for pointing this out.)  Also, the
3614    leapseconds.awk file is no longer distributed in the tzcode
3615    tarball, since it belongs in the tzdata tarball (where 2014f
3616    inadvertently also distributed it).
3617
3618  Changes affecting documentation and commentary
3619
3620    A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
3621    suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
3622    for debugging it.)
3623
3624    The man pages have been updated to use function prototypes,
3625    to document thread-safe variants like localtime_r, and to document
3626    the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
3627    mktime_z.
3628
3629    The fields in Link lines have been renamed to be more descriptive
3630    and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
3631    and LINK-TO has become LINK-NAME.
3632
3633    tz-link.htm mentions the IETF's tzdist working group; Windows
3634    Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
3635
3636    Some broken URLs have been fixed in the commentary.  (Thanks to
3637    Lester Caine.)
3638
3639    Commentary about Philippines DST has been updated, and commentary
3640    on pre-1970 time in India has been added.
3641
3642
3643Release 2014f - 2014-08-05 17:42:36 -0700
3644
3645  Changes affecting future timestamps
3646
3647    Russia will subtract an hour from most of its time zones on 2014-10-26
3648    at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
3649    There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
3650    Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
3651    (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
3652    (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
3653    (Europe/Samara) are not changing their clocks.  The changed zones are
3654    Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
3655    Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
3656    Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
3657    Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
3658    subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
3659    but not its UTC offset.  Two zones are added: Asia/Chita (split
3660    from Asia/Yakutsk, and also with two hours subtracted) and
3661    Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
3662    subtracted).  (Thanks to Tim Parenti for much of the above.)
3663
3664  Changes affecting time zone abbreviations
3665
3666    Australian eastern time zone abbreviations are now AEST/AEDT not EST,
3667    and similarly for the other Australian zones.  That is, for eastern
3668    standard and daylight saving time the abbreviations are AEST and AEDT
3669    instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
3670    and AWST/AWDT are now used instead of the former CST, CWST, and WST.
3671    This change does not affect UT offsets, only time zone abbreviations.
3672    (Thanks to Rich Tibbett and many others.)
3673
3674    Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
3675    effective 2014-10-26 at 02:00 local time.
3676
3677    The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
3678    has been changed from URUT to XJT.  (Thanks to Luther Ma.)
3679
3680    Prefer MSK/MSD for Moscow time in Russia, even in other cities.
3681    Similarly, prefer EET/EEST for eastern European time in Russia.
3682
3683    Change time zone abbreviations in (western) Samoa to use "ST" and
3684    "DT" suffixes, as this is more likely to match common practice.
3685    Prefix "W" to (western) Samoa time when its standard-time offset
3686    disagrees with that of American Samoa.
3687
3688    America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
3689
3690    Time zone abbreviations have been updated for Japan's two time
3691    zones used 1896-1937.  JWST now stands for Western Standard
3692    Time, and JCST for Central Standard Time (formerly this was CJT).
3693    These abbreviations are now used for time in Korea, Taiwan,
3694    and Sakhalin while controlled by Japan.
3695
3696  Changes affecting past timestamps
3697
3698    China's five zones have been simplified to two, since the post-1970
3699    differences in the other three seem to have been imaginary.  The
3700    zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
3701    removed; backwards-compatibility links still work, albeit with
3702    different behaviors for timestamps before May 1980.  Asia/Urumqi's
3703    1980 transition to UT +08 has been removed, so that it is now at
3704    +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
3705    Treindl sent helpful translations of two papers by Guo Qingsheng.)
3706
3707    Some zones have been turned into links, when they differed from existing
3708    zones only for older UT offsets where data entries were likely invented.
3709    These changes affect UT offsets in pre-1970 timestamps only.  This is
3710    similar to the change in release 2013e, except this time for western
3711    Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
3712    Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
3713    Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
3714    Atlantic/St_Helena.  This also affects the backwards-compatibility
3715    link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
3716    Tim Parenti, and David Patte for reporting problems in earlier
3717    versions of this change.)
3718
3719    Asia/Shanghai's pre-standard-time UT offset has been changed from
3720    8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
3721    transition to standard time has been changed from 1928 to 1901.
3722
3723    Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
3724    then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
3725    In 1946 it observed DST from 05-15 through 09-30; in 1947
3726    from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
3727    (Thanks to Yu-Cheng Chuang.)
3728
3729    Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
3730
3731    Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
3732    10-03 at 00:00.  (Thanks to Konstantin Hyppönen.)
3733
3734    Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
3735    period from 1911 to 1950.
3736
3737    Pacific/Chatham has been changed to New Zealand standard time plus
3738    45 minutes for the period before 1957, reflecting a 1956 remark in
3739    the New Zealand parliament.
3740
3741    Europe/Budapest has several pre-1946 corrections: in 1918 the transition
3742    out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
3743    1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
3744    not 04-06 at 02:00; and there was no DST in 1920.
3745
3746    Africa/Accra is now assumed to have observed DST from 1920 through 1935.
3747
3748    Time in Russia before 1927 or so has been corrected by a few seconds in
3749    the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
3750    Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
3751    Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
3752    point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
3753
3754  Changes affecting data format
3755
3756    A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
3757    The new file's extended format allows multiple country codes per zone.
3758    The older file is still installed but is deprecated; its format is
3759    not changing and it will still be distributed for a while, but new
3760    applications should use the new file.
3761
3762    The new file format simplifies maintenance of obscure locations.
3763    To test this, it adds coverage for the Crozet Islands and the
3764    Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
3765
3766    The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
3767    It is still ASCII now, but commentary about the switch has been added.
3768    The new file 'zone1970.tab' already uses UTF-8.
3769
3770  Changes affecting code
3771
3772    'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
3773    is defined.  (Thanks to Elliott Hughes for reporting the problem.)
3774
3775    'zic' no longer mishandles input when ignoring case in locales that
3776    are not compatible with English, e.g., unibyte Turkish locales when
3777    compiled with HAVE_GETTEXT.
3778
3779    Error diagnostics of 'zic' and 'yearistype' have been reworded so that
3780    they no longer use ASCII '-' as if it were a dash.
3781
3782    'zic' now rejects output file names that contain '.' or '..' components.
3783    (Thanks to Tim Parenti for reporting the problem.)
3784
3785    'zic -v' now warns about output file names that do not follow
3786    POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
3787    David Olson for starting the ball rolling on this.)
3788
3789    Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
3790
3791  Changes affecting build procedure
3792
3793    'zic' no longer links in localtime.o and asctime.o, as they're not needed.
3794    (Thanks to John Cochran.)
3795
3796  Changes affecting documentation and commentary
3797
3798    The 'Theory' file documents legacy names, the longstanding
3799    exceptions to the POSIX-inspired file name rules.
3800
3801    The 'zic' documentation clarifies the role of time types when
3802    interpreting dates.  (Thanks to Arthur David Olson.)
3803
3804    Documentation and commentary now prefer UTF-8 to US-ASCII,
3805    allowing the use of proper accents in foreign words and names.
3806    Code and data have not changed because of this.  (Thanks to
3807    Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
3808    this.)
3809
3810    Non-HTML documentation and commentary now use plain-text URLs instead of
3811    HTML insertions, and are more consistent about bracketing URLs when they
3812    are not already surrounded by white space.  (Thanks to suggestions by
3813    Steffen Nurpmeso.)
3814
3815    There is new commentary about Xujiahui Observatory, the five time-zone
3816    project in China from 1918 to 1949, timekeeping in Japanese-occupied
3817    Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
3818    warlord Jin Shuren in the data.
3819
3820    Commentary about the coverage of each Russian zone has been standardized.
3821    (Thanks to Tim Parenti.)
3822
3823    There is new commentary about contemporary timekeeping in Ethiopia.
3824
3825    Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
3826
3827    There is new commentary about time in Poland in 1919.
3828
3829    Proper credit has been given to DST inventor George Vernon Hudson.
3830
3831    Commentary about time in Metlakatla, AK and Resolute, NU has been
3832    improved, with a new source for the former.
3833
3834    In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
3835    is uninhabited.
3836
3837    Commentary about permanent Antarctic bases has been updated.
3838
3839    Several typos have been corrected.  (Thanks to Tim Parenti for
3840    contributing some of these fixes.)
3841
3842    tz-link.htm now mentions the JavaScript libraries Moment Timezone,
3843    TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
3844    from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
3845    (Thanks to a heads-up from Dirkjan Ochtman.)
3846
3847    The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
3848    have been removed.  These obsolescent US Naval Observatory entries were no
3849    longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
3850
3851
3852Release 2014e - 2014-06-12 21:53:52 -0700
3853
3854  Changes affecting near-future timestamps
3855
3856    Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
3857    (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
3858    switch to standard time at 24:00 the last Thursday before Ramadan, and
3859    back to DST at 00:00 the first Friday after Ramadan.
3860
3861    Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
3862    to Milamber Space Network.)  Guess that from 2015 on Morocco will
3863    temporarily switch to standard time at 03:00 the last Saturday before
3864    Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
3865
3866  Changes affecting past timestamps
3867
3868    The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
3869    "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
3870    "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
3871    in 1991.  (Thanks to Hank W. for reporting the problems.)
3872
3873  Changes affecting commentary
3874
3875    tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
3876    draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
3877    removes stale pointers to World Time Explorer and WORLDTIME.
3878
3879
3880Release 2014d - 2014-05-27 21:34:40 -0700
3881
3882  Changes affecting code
3883
3884    zic no longer generates files containing timestamps before the Big Bang.
3885    This works around GNOME glib bug 878
3886    <https://gitlab.gnome.org/GNOME/glib/issues/878>
3887    (Thanks to Leonardo Chiquitto for reporting the bug, and to
3888    Arthur David Olson and James Cloos for suggesting improvements to the fix.)
3889
3890  Changes affecting documentation
3891
3892    tz-link.htm now mentions GNOME.
3893
3894
3895Release 2014c - 2014-05-13 07:44:13 -0700
3896
3897  Changes affecting near-future timestamps
3898
3899    Egypt observes DST starting 2014-05-15 at 24:00.
3900    (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
3901    Details have not been announced, except that DST will not be observed
3902    during Ramadan.  Guess that DST will stop during the same Ramadan dates as
3903    Morocco, and that Egypt's future spring and fall transitions will be the
3904    same as 2010 when it last observed DST, namely April's last Friday at
3905    00:00 to September's last Thursday at 23:00 standard time.  Also, guess
3906    that Ramadan transitions will be at 00:00 standard time.
3907
3908  Changes affecting code
3909
3910    zic now generates transitions for minimum time values, eliminating guesswork
3911    when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
3912
3913    Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
3914
3915  Changes affecting commentary and documentation
3916
3917    Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
3918
3919
3920Release 2014b - 2014-03-24 21:28:50 -0700
3921
3922  Changes affecting near-future timestamps
3923
3924    Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
3925    (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
3926
3927    New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
3928    Bengt-Inge Larsson.)  This is currently an approximation; a better version
3929    will require the zic and localtime fixes mentioned below, and the plan is
3930    to wait for a while until at least the zic fixes propagate.
3931
3932  Changes affecting code
3933
3934    'zic' and 'localtime' no longer reject locations needing four transitions
3935    per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
3936    Also, 'zic' avoids some unlikely failures due to integer overflow.
3937
3938  Changes affecting build procedure
3939
3940    'make check' now detects Rule lines defined but never used.
3941    The NZAQ rules, an instance of this problem, have been removed.
3942
3943  Changes affecting commentary and documentation
3944
3945    Fix Tuesday/Thursday typo in description of time in Israel.
3946    (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
3947
3948    Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
3949    to Donald MacQueen.)  Instead, the Microsoft Windows Store app
3950    library supports them.
3951
3952    Add comments about Johnston Island time in the 1960s.
3953    (Thanks to Lyle McElhaney.)
3954
3955    Morocco's 2014 DST start will be as predicted.
3956    (Thanks to Sebastien Willemijns.)
3957
3958
3959Release 2014a - 2014-03-07 23:30:29 -0800
3960
3961  Changes affecting near-future timestamps
3962
3963    Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
3964    the heads-up, and to Tim Parenti for simplifying the update.)
3965
3966  Changes affecting past timestamps
3967
3968    Fiji ended DST on 2014-01-19 at 02:00, not the previously scheduled 03:00.
3969    (Thanks to Steffen Thorsen.)
3970
3971    Ukraine switched from Moscow to Eastern European time on 1990-07-01
3972    (not 1992-01-01), and observed DST during the entire next winter.
3973    (Thanks to Vladimir in Moscow via Alois Treindl.)
3974
3975    In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
3976    (Thanks to Avigdor Finkelstein.)
3977
3978  Changes affecting code
3979
3980    A uninitialized-storage bug in 'localtime' has been fixed.
3981    (Thanks to Logan Chien.)
3982
3983  Changes affecting the build procedure
3984
3985    The settings for 'make check_web' now default to Ubuntu 13.10.
3986
3987  Changes affecting commentary and documentation
3988
3989    The boundary of the US Pacific time zone is given more accurately.
3990    (Thanks to Alan Mintz.)
3991
3992    Chile's 2014 DST will be as predicted.  (Thanks to José Miguel Garrido.)
3993
3994    Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raúl Perasso.)
3995
3996    Better descriptions of countries with same time zone history as
3997    Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
3998
3999    Several changes affect tz-link.htm, the main web page.
4000
4001      Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
4002      David Braverman).
4003
4004      Mention xCal (Internet RFC 6321) and jCal.
4005
4006      Microsoft has some support for tz database names.
4007
4008      CLDR data formats include both XML and JSON.
4009
4010      Mention Maggiolo's map of solar vs standard time.
4011      (Thanks to Arthur David Olson.)
4012
4013      Mention TZ4Net.  (Thanks to Matt Johnson.)
4014
4015      Mention the timezone-olson Haskell package.
4016
4017      Mention zeitverschiebung.net.  (Thanks to Martin Jäger.)
4018
4019      Remove moribund links to daylight-savings-time.info and to
4020      Simple Timer + Clocks.
4021
4022      Update two links.  (Thanks to Oscar van Vlijmen.)
4023
4024      Fix some formatting glitches, e.g., remove random newlines from
4025      abbr elements' title attributes.
4026
4027
4028Release 2013i - 2013-12-17 07:25:23 -0800
4029
4030  Changes affecting near-future timestamps:
4031
4032    Jordan switches back to standard time at 00:00 on December 20, 2013.
4033    The 2006-2011 transition schedule is planned to resume in 2014.
4034    (Thanks to Steffen Thorsen.)
4035
4036  Changes affecting past timestamps:
4037
4038    In 2004, Cuba began DST on March 28, not April 4.
4039    (Thanks to Steffen Thorsen.)
4040
4041  Changes affecting code
4042
4043    The compile-time flag NOSOLAR has been removed, as nowadays the
4044    benefit of slightly shrinking runtime table size is outweighed by the
4045    cost of disallowing potential future updates that exceed old limits.
4046
4047  Changes affecting documentation and commentary
4048
4049    The files solar87, solar88, and solar89 are no longer distributed.
4050    They were a negative experiment - that is, a demonstration that
4051    tz data can represent solar time only with some difficulty and error.
4052    Their presence in the distribution caused confusion, as Riyadh
4053    civil time was generally not solar time in those years.
4054
4055    tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
4056
4057
4058Release 2013h - 2013-10-25 15:32:32 -0700
4059
4060  Changes affecting current and future timestamps:
4061
4062    Libya has switched its UT offset back to +02 without DST, instead
4063    of +01 with DST.  (Thanks to Even Scharning.)
4064
4065    Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
4066    (Thanks to Gwillim Law.)
4067
4068  Changes affecting future timestamps:
4069
4070    Acre and (we guess) western Amazonas will switch from UT -04 to -05
4071    on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
4072    (Thanks to Steffen Thorsen.)
4073
4074    Add entries for DST transitions in Morocco in the year 2038.
4075    This avoids some year-2038 glitches introduced in 2013g.
4076    (Thanks to Yoshito Umaoka for reporting the problem.)
4077
4078  Changes affecting API
4079
4080    The 'tzselect' command no longer requires the 'select' command,
4081    and should now work with /bin/sh on more platforms.  It also works
4082    around a bug in BusyBox awk before version 1.21.0.  (Thanks to
4083    Patrick 'P. J.' McDermott and Alan Barrett.)
4084
4085  Changes affecting code
4086
4087    Fix localtime overflow bugs with 32-bit unsigned time_t.
4088
4089    zdump no longer assumes sscanf returns maximal values on overflow.
4090
4091  Changes affecting the build procedure
4092
4093    The builder can specify which programs to use, if any, instead of
4094    'ar' and 'ranlib', and libtz.a is now built locally before being
4095    installed.  (Thanks to Michael Forney.)
4096
4097    A dependency typo in the 'zdump' rule has been fixed.
4098    (Thanks to Andrew Paprocki.)
4099
4100    The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
4101    work as specified by POSIX.2-1992 or later; this is portable nowadays.
4102
4103    'make clean' no longer removes 'leapseconds', since it's
4104    host-independent and is part of the distribution.
4105
4106    The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
4107
4108  Changes affecting documentation and commentary
4109
4110    tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
4111    (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
4112
4113    Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
4114    8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
4115    longer maintained) and for old advisories.  SOFA now does C.
4116
4117Release 2013g - 2013-09-30 21:08:26 -0700
4118
4119  Changes affecting current and near-future timestamps
4120
4121    Morocco now observes DST from the last Sunday in March to the last
4122    Sunday in October, not April to September respectively.  (Thanks
4123    to Steffen Thorsen.)
4124
4125  Changes affecting 'zic'
4126
4127    'zic' now runs on platforms that lack both hard links and symlinks.
4128    (Thanks to Theo Veenker for reporting the problem, for MinGW.)
4129    Also, fix some bugs on platforms that lack hard links but have symlinks.
4130
4131    'zic -v' again warns that Asia/Tehran has no POSIX environment variable
4132    to predict the far future, fixing a bug introduced in 2013e.
4133
4134  Changes affecting the build procedure
4135
4136    The 'leapseconds' file is again put into the tzdata tarball.
4137    Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
4138    Matt Burgess and Ian Abbott.)  The timestamps of these and other
4139    dependent files in tarballs are adjusted more consistently.
4140
4141  Changes affecting documentation and commentary
4142
4143    The README file is now part of the data tarball as well as the code.
4144    It now states that files are public domain unless otherwise specified.
4145    (Thanks to Andrew Main (Zefram) for asking for clarifications.)
4146    Its details about the 1989 release moved to a place of honor near
4147    the end of NEWS.
4148
4149
4150Release 2013f - 2013-09-24 23:37:36 -0700
4151
4152  Changes affecting near-future timestamps
4153
4154    Tocantins will very likely not observe DST starting this spring.
4155    (Thanks to Steffen Thorsen.)
4156
4157    Jordan will likely stay at UT +03 indefinitely, and will not fall
4158    back this fall.
4159
4160    Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
4161
4162  Changes affecting API
4163
4164    The types of the global variables 'timezone' and 'altzone' (if present)
4165    have been changed back to 'long'.  This is required for 'timezone'
4166    by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
4167    These variables were originally 'long' in the tz code, but were
4168    mistakenly changed to 'time_t' in 1987; nobody reported the
4169    incompatibility until now.  The difference matters on x32, where
4170    'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
4171
4172  Changes affecting the build procedure
4173
4174    Avoid long strings in leapseconds.awk to work around a mawk bug.
4175    (Thanks to Cyril Baurand.)
4176
4177  Changes affecting documentation and commentary
4178
4179    New file 'NEWS' that contains release notes like this one.
4180
4181    Paraguay's law does not specify DST transition time; 00:00 is customary.
4182    (Thanks to Waldemar Villamayor-Venialbo.)
4183
4184    Minor capitalization fixes.
4185
4186  Changes affecting version-control only
4187
4188    The experimental GitHub repository now contains annotated and
4189    signed tags for recent releases, e.g., '2013e' for Release 2013e.
4190    Releases are tagged starting with 2012e; earlier releases were
4191    done differently, and tags would either not have a simple name or
4192    not exactly match what was released.
4193
4194    'make set-timestamps' is now simpler and a bit more portable.
4195
4196
4197Release 2013e - 2013-09-19 23:50:04 -0700
4198
4199  Changes affecting near-future timestamps
4200
4201    This year Fiji will start DST on October 27, not October 20.
4202    (Thanks to David Wheeler for the heads-up.)  For now, guess that
4203    Fiji will continue to spring forward the Sunday before the fourth
4204    Monday in October.
4205
4206  Changes affecting current and future time zone abbreviations
4207
4208    Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
4209    time zone abbreviations since 1932.  (Thanks to George Ziegler,
4210    Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
4211    Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
4212    Asia/Makassar, and Asia/Pontianak.
4213
4214    Use ART (UT -03, standard time), rather than WARST (also -03, but
4215    daylight saving time) for San Luis, Argentina since 2009.
4216
4217  Changes affecting Godthåb timestamps after 2037 if version mismatch
4218
4219    Allow POSIX-like TZ strings where the transition time's hour can
4220    range from -167 through 167, instead of the POSIX-required 0
4221    through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
4222    new Fiji rules.  This is a more compact way to represent
4223    far-future timestamps for America/Godthab, America/Santiago,
4224    Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
4225    Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
4226    this change.  (Derived from a suggestion by Arthur David Olson.)
4227
4228    Allow POSIX-like TZ strings where daylight saving time is in
4229    effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
4230    Argentina Summer Time all year.  This supports a more compact way
4231    to represent the 2013d data for America/Argentina/San_Luis.
4232    Because of the change for San Luis noted above this change does not
4233    affect the current data.  (Thanks to Andrew Main (Zefram) for
4234    suggestions that improved this change.)
4235
4236    Where these two TZ changes take effect, there is a minor extension
4237    to the tz file format in that it allows new values for the
4238    embedded TZ-format string, and the tz file format version number
4239    has therefore been increased from 2 to 3 as a precaution.
4240    Version-2-based client code should continue to work as before for
4241    all timestamps before 2038.  Existing version-2-based client code
4242    (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
4243    files, and typically works in practice even for timestamps after
4244    2037; the only known exception is America/Godthab.
4245
4246  Changes affecting timestamps before 1970
4247
4248    Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
4249    some errors before 1947.
4250
4251    Some zones have been turned into links, when they differ from existing
4252    zones only in older data entries that were likely invented or that
4253    differ only in LMT or transitions from LMT.  These changes affect
4254    only timestamps before 1943.  The affected zones are:
4255    Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
4256    America/Grenada, America/Guadeloupe, America/Marigot,
4257    America/Montserrat, America/St_Barthelemy, America/St_Kitts,
4258    America/St_Lucia, America/St_Thomas, America/St_Vincent,
4259    America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
4260    confirming that the old Europe/Vaduz zone was wrong and the new
4261    link is better for WWII-era times.)
4262
4263    Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
4264    America/Cayman, America/Jamaica and America/Grand_Turk timestamps
4265    from 1890 to 1912.
4266
4267    Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
4268    This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
4269    to Alois Treindl.)
4270
4271    Change the date of the circa-1850 Zurich transition from 1849-09-12
4272    to 1853-07-16, overriding Shanks with data from Messerli about
4273    postal and telegraph time in Switzerland.
4274
4275  Changes affecting time zone abbreviations before 1970
4276
4277    For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
4278    as Jakarta was called Batavia back then.
4279
4280  Changes affecting API
4281
4282    The 'zic' command now outputs a dummy transition when far-future
4283    data can't be summarized using a TZ string, and uses a 402-year
4284    window rather than a 400-year window.  For the current data, this
4285    affects only the Asia/Tehran file.  It does not affect any of the
4286    timestamps that this file represents, so zdump outputs the same
4287    information as before.  (Thanks to Andrew Main (Zefram).)
4288
4289    The 'date' command has a new '-r' option, which lets you specify
4290    the integer time to display, a la FreeBSD.
4291
4292    The 'tzselect' command has two new options '-c' and '-n', which lets you
4293    select a zone based on latitude and longitude.
4294
4295    The 'zic' command's '-v' option now warns about constructs that
4296    require the new version-3 binary file format.  (Thanks to Arthur
4297    David Olson for the suggestion.)
4298
4299    Support for floating-point time_t has been removed.
4300    It was always dicey, and POSIX no longer requires it.
4301    (Thanks to Eric Blake for suggesting to the POSIX committee to
4302    remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
4303    Heninger, Arthur David Olson, and Alois Treindl, for reporting
4304    bugs and elucidating some of the corners of the old floating-point
4305    implementation.)
4306
4307    The signatures of 'offtime', 'timeoff', and 'gtime' have been
4308    changed back to the old practice of using 'long' to represent UT
4309    offsets.  This had been inadvertently and mistakenly changed to
4310    'int_fast32_t'.  (Thanks to Christos Zoulas.)
4311
4312    The code avoids undefined behavior on integer overflow in some
4313    more places, including gmtime, localtime, mktime and zdump.
4314
4315  Changes affecting the zdump utility
4316
4317    zdump now outputs "UT" when referring to Universal Time, not "UTC".
4318    "UTC" does not make sense for timestamps that predate the introduction
4319    of UTC, whereas "UT", a more generic term, does.  (Thanks to Steve Allen
4320    for clarifying UT vs UTC.)
4321
4322  Data changes affecting behavior of tzselect and similar programs
4323
4324    Country code BQ is now called the more common name "Caribbean Netherlands"
4325    rather than the more official "Bonaire, St Eustatius & Saba".
4326
4327    Remove from zone.tab the names America/Montreal, America/Shiprock,
4328    and Antarctica/South_Pole, as they are equivalent to existing
4329    same-country-code zones for post-1970 timestamps.  The data entries for
4330    these names are unchanged, so the names continue to work as before.
4331
4332  Changes affecting code internals
4333
4334    zic -c now runs way faster on 64-bit hosts when given large numbers.
4335
4336    zic now uses vfprintf to avoid allocating and freeing some memory.
4337
4338    tzselect now computes the list of continents from the data,
4339    rather than have it hard-coded.
4340
4341    Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
4342
4343  Changes affecting the build procedure
4344
4345    The 'leapseconds' file is now generated automatically from a
4346    new file 'leap-seconds.list', which is a copy of
4347    <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
4348    A new source file 'leapseconds.awk' implements this.
4349    The goal is simplification of the future maintenance of 'leapseconds'.
4350
4351    When building the 'posix' or 'right' subdirectories, if the
4352    subdirectory would be a copy of the default subdirectory, it is
4353    now made a symbolic link if that is supported.  This saves about
4354    2 MB of file system space.
4355
4356    The links America/Shiprock and Antarctica/South_Pole have been
4357    moved to the 'backward' file.  This affects only nondefault builds
4358    that omit 'backward'.
4359
4360  Changes affecting version-control only
4361
4362    .gitignore now ignores 'date'.
4363
4364  Changes affecting documentation and commentary
4365
4366    Changes to the 'tzfile' man page
4367
4368      It now mentions that the binary file format may be extended in
4369      future versions by appending data.
4370
4371      It now refers to the 'zdump' and 'zic' man pages.
4372
4373    Changes to the 'zic' man page
4374
4375      It lists conditions that elicit a warning with '-v'.
4376
4377      It says that the behavior is unspecified when duplicate names
4378      are given, or if the source of one link is the target of another.
4379
4380      Its examples are updated to match the latest data.
4381
4382      The definition of white space has been clarified slightly.
4383      (Thanks to Michael Deckers.)
4384
4385    Changes to the 'Theory' file
4386
4387      There is a new section about the accuracy of the tz database,
4388      describing the many ways that errors can creep in, and
4389      explaining why so many of the pre-1970 timestamps are wrong or
4390      misleading (thanks to Steve Allen, Lester Caine, and Garrett
4391      Wollman for discussions that contributed to this).
4392
4393      The 'Theory' file describes LMT better (this follows a
4394      suggestion by Guy Harris).
4395
4396      It refers to the 2013 edition of POSIX rather than the 2004 edition.
4397
4398      It's mentioned that excluding 'backward' should not affect the
4399      other data, and it suggests at least one zone.tab name per
4400      inhabited country (thanks to Stephen Colebourne).
4401
4402      Some longstanding restrictions on names are documented, e.g.,
4403      'America/New_York' precludes 'America/New_York/Bronx'.
4404
4405      It gives more reasons for the 1970 cutoff.
4406
4407      It now mentions which time_t variants are supported, such as
4408      signed integer time_t.  (Thanks to Paul Goyette for reporting
4409      typos in an experimental version of this change.)
4410
4411      (Thanks to Philip Newton for correcting typos in these changes.)
4412
4413    Documentation and commentary is more careful to distinguish UT in
4414    general from UTC in particular.  (Thanks to Steve Allen.)
4415
4416    Add a better source for the Zurich 1894 transition.
4417    (Thanks to Pierre-Yves Berger.)
4418
4419    Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
4420
4421
4422Release 2013d - 2013-07-05 07:38:01 -0700
4423
4424  Changes affecting future timestamps:
4425
4426    Morocco's midsummer transitions this year are July 7 and August 10,
4427    not July 9 and August 8.  (Thanks to Andrew Paprocki.)
4428
4429    Israel now falls back on the last Sunday of October.
4430    (Thanks to Ephraim Silverberg.)
4431
4432  Changes affecting past timestamps:
4433
4434    Specify Jerusalem's location more precisely; this changes the pre-1880
4435    times by 2 s.
4436
4437  Changing affecting metadata only:
4438
4439    Fix typos in the entries for country codes BQ and SX.
4440
4441  Changes affecting code:
4442
4443    Rework the code to fix a bug with handling Australia/Macquarie on
4444    32-bit hosts (thanks to Arthur David Olson).
4445
4446    Port to platforms like NetBSD, where time_t can be wider than long.
4447
4448    Add support for testing time_t types other than the system's.
4449    Run 'make check_time_t_alternatives' to try this out.
4450    Currently, the tests fail for unsigned time_t;
4451    this should get fixed at some point.
4452
4453  Changes affecting documentation and commentary:
4454
4455    Deemphasize the significance of national borders.
4456
4457    Update the zdump man page.
4458
4459    Remove obsolete NOID comment (thanks to Denis Excoffier).
4460
4461    Update several URLs and comments in the web pages.
4462
4463    Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
4464
4465    Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
4466
4467
4468Release 2013c - 2013-04-19 16:17:40 -0700
4469
4470  Changes affecting current and future timestamps:
4471
4472    Palestine observed DST starting March 29, 2013.  (Thanks to
4473    Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
4474    with the predicted rules being the last Thursday in March at 24:00
4475    to the first Friday on or after September 21 at 01:00.
4476
4477    Assume that the recent change to Paraguay's DST rules is permanent,
4478    by moving the end of DST to the 4th Sunday in March every year.
4479    (Thanks to Carlos Raúl Perasso.)
4480
4481  Changes affecting past timestamps:
4482
4483    Fix some historical data for Palestine to agree with that of
4484    timeanddate.com, as follows:
4485
4486	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
4487	  00:00 Apr 1.
4488
4489	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
4490	  02:00.
4491
4492	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
4493
4494	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
4495
4496	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
4497
4498	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
4499
4500    Fix times of habitation for Macquarie to agree with the Tasmania
4501    Parks & Wildlife Service history, which indicates that permanent
4502    habitation was 1899-1919 and 1948 on.
4503
4504  Changing affecting metadata only:
4505
4506    Macquarie Island is politically part of Australia, not Antarctica.
4507    (Thanks to Tobias Conradi.)
4508
4509    Sort Macquarie more consistently with other parts of Australia.
4510    (Thanks to Tim Parenti.)
4511
4512
4513Release 2013b - 2013-03-10 22:33:40 -0700
4514
4515  Changes affecting current and future timestamps:
4516
4517    Haiti uses US daylight-saving rules this year, and presumably future years.
4518    This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
4519
4520    Paraguay will end DST on March 24 this year.
4521    (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
4522
4523    Morocco does not observe DST during Ramadan;
4524    try to predict Ramadan in Morocco as best we can.
4525    (Thanks to Erik Homoet for the heads-up.)
4526
4527  Changes affecting commentary:
4528
4529    Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
4530    Update URL for Solaris.  Mention Internet RFC 6557.
4531    Update Internet RFCs 2445->5545, 2822->5322.
4532    Switch from FTP to HTTP for Internet RFCs.
4533
4534
4535Release 2013a - 2013-02-27 09:20:35 -0800
4536
4537  Change affecting binary data format:
4538
4539    The zone offset at the end of version-2-format zone files is now
4540    allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
4541
4542  Changes affecting current and future timestamps:
4543
4544    Chile's 2013 rules, and we guess rules for 2014 and later, will be
4545    the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
4546    (Thanks to Steffen Thorsen and Robert Elz.)
4547
4548    New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
4549    (Thanks to Tobias Conradi and Arthur David Olson.)
4550
4551  Many changes affect historical timestamps before 1940.
4552  These were deduced from: Milne J. Civil time. Geogr J. 1899
4553  Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
4554
4555  Changes affecting the code:
4556
4557    Fix zic bug that mishandled Egypt's 2010 changes (this also affected
4558    the data).  (Thanks to Arthur David Olson.)
4559
4560    Fix localtime bug when time_t is unsigned and data files were generated
4561    by a signed time_t system.  (Thanks to Doug Bailey for reporting and
4562    to Arthur David Olson for fixing.)
4563
4564    Allow the email address for bug reports to be set by the packager.
4565    The default is tz@iana.org, as before.  (Thanks to Joseph S. Myers.)
4566
4567    Update HTML checking to be compatible with Ubuntu 12.10.
4568
4569    Check that files are a safe subset of ASCII.  At some point we may
4570    relax this requirement to a safe subset of UTF-8.  Without the
4571    check, some non-UTF-8 encodings were leaking into the distribution.
4572
4573  Commentary changes:
4574
4575    Restore a comment about copyright notices that was inadvertently deleted.
4576    (Thanks to Arthur David Olson.)
4577
4578    Improve the commentary about which districts observe what times
4579    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
4580
4581    Add web page links to tz.js.
4582
4583    Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
4584
4585
4586Release 2012j - 2012-11-12 18:34:49 -0800
4587
4588  Libya moved to CET this weekend, but with DST planned next year.
4589  (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
4590
4591  Signatures now have the extension .asc, not .sign, as that's more
4592  standard.  (Thanks to Phil Pennock.)
4593
4594  The output of 'zdump --version', and of 'zic --version', now
4595  uses a format that is more typical for --version.
4596  (Thanks to Joseph S. Myers.)
4597
4598  The output of 'tzselect --help', 'zdump --help', and 'zic --help'
4599  now uses tz@iana.org rather than the old elsie address.
4600
4601  zic -v now complains about abbreviations that are less than 3
4602  or more than 6 characters, as per POSIX.  Formerly, it checked
4603  for abbreviations that were more than 3.
4604
4605  'make public' no longer puts its temporary directory under /tmp,
4606  and uses the just-built zic rather than the system zic.
4607
4608  Various fixes to documentation and commentary.
4609
4610
4611Release 2012i - 2012-11-03 12:57:09 -0700
4612
4613  Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
4614
4615  Linker flags can now be specified via LDFLAGS.
4616  AWK now defaults to 'awk', not 'nawk'.
4617  The shell in tzselect now defaults to /bin/bash, but this can
4618  be overridden by specifying KSHELL.
4619  The main web page now mentions the unofficial GitHub repository.
4620  (Thanks to Mike Frysinger.)
4621
4622  Tarball signatures can now be built by running 'make signatures'.
4623  There are also new makefile rules 'tarballs', 'check_public', and
4624  separate makefile rules for each tarball and signature file.
4625  A few makefile rules are now more portable to strict POSIX.
4626
4627  The main web page now lists the canonical IANA URL.
4628
4629
4630Release 2012h - 2012-10-26 22:49:10 -0700
4631
4632  Bahia no longer has DST.  (Thanks to Kelley Cook.)
4633
4634  Tocantins has DST.  (Thanks to Rodrigo Severo.)
4635
4636  Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
4637
4638  Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
4639
4640  Web page updates.
4641
4642  More C modernization, except that at Arthur David Olson's suggestion
4643  the instances of 'register' were kept.
4644
4645
4646Release 2012g - 2012-10-17 20:59:45 -0700
4647
4648  Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
4649
4650  Palestine fall 2012.  (Thanks to Steffen Thorsen.)
4651
4652  Assume C89.
4653
4654  To attack the version-number problem, this release ships the file
4655  'Makefile' (which contains the release number) in both the tzcode and
4656  the tzdata tarballs.  The two Makefiles are identical, and should be
4657  identical in any matching pair of tarballs, so it shouldn't matter
4658  which order you extract the tarballs.  Perhaps we can come up with a
4659  better version-number scheme at some point; this scheme does have the
4660  virtue of not adding more files.
4661
4662
4663Release 2012f - 2012-09-12 23:17:03 -0700
4664
4665  * australasia (Pacific/Fiji): Fiji DST is October 21 through January
4666    20 this year.  (Thanks to Steffen Thorsen.)
4667
4668
4669Release 2012e - 2012-08-02 20:44:55 -0700
4670
4671  * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
4672    (Thanks to Steffen Thorsen.)
4673
4674  * Use a single version number for both code and data.
4675
4676  * .gitignore: New file.
4677
4678  * Remove trailing white space.
4679
4680
4681Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
4682
4683  Changes for Morocco's timestamps, which take effect in a couple of
4684  hours, along with infrastructure changes to accommodate how the tz
4685  code and data are released on IANA.
4686
4687
4688Release data2012c - 2012-03-27 12:17:25 -0400
4689
4690  africa
4691	Summer time changes for Morocco (to start late April 2012)
4692
4693  asia
4694	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
4695
4696  northamerica
4697	Haiti following US/Canada rules for 2012 (and we're assuming,
4698	for now anyway, for the future).
4699
4700
4701Release 2012b - 2012-03-02 12:29:15 +0700
4702
4703  There is just one change to tzcode2012b (compared with 2012a):
4704  the Makefile that was accidentally included with 2012a has been
4705  replaced with the version that should have been there, which is
4706  identical with the previous version (from tzcode2011i).
4707
4708  There are just two changes in tzdata2012b compared with 2012a.
4709
4710  Most significantly, summer time in Cuba has been delayed 3 weeks
4711  (now starts April 1 rather than March 11).   Since Mar 11 (the old start
4712  date, as listed in 2012a) is just a little over a week away, this
4713  change is urgent.
4714
4715  Less importantly, an excess tab in one of the changes in zone.tab
4716  in 2012a has been removed.
4717
4718
4719Release 2012a - 2012-03-01 18:28:10 +0700
4720
4721  The changes in tzcode2012a (compared to the previous version, 2011i)
4722  are entirely to the README and tz-art.htm and tz-link.htm files, if
4723  none of those concern you, you can ignore the code update.  The changes
4724  reflect the changed addresses for the mailing list and the code and
4725  data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
4726  has been added to tz-link.htm).
4727
4728  In tzdata2012a (compared to the previous release, which was 2011n)
4729  the major changes are:
4730	Chile 2011/2012 and 2012/2013 summer time date adjustments.
4731	Falkland Islands onto permanent summer time (we're assuming for the
4732		foreseeable future, though 2012 is all we're fairly certain of.)
4733	Armenia has abolished Summer Time.
4734	Tokelau jumped the International Date Line back last December
4735		(just the same as their near neighbour, Samoa).
4736	America/Creston is a new zone for a small area of British Columbia
4737	There will be a leapsecond 2012-06-30 23:59:60 UTC.
4738
4739  Other minor changes are:
4740	Corrections to 1918 Canadian summer time end dates.
4741	Updated URL for UK time zone history (in comments)
4742	A few typos in Le Corre's list of free French place names (comments)
4743
4744
4745Release data2011n - 2011-10-30 14:57:54 +0700
4746
4747  There are three changes of note - most urgently, Cuba (America/Havana)
4748  has extended summer time by two weeks, now to end on Nov 13, rather than
4749  the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
4750  (Europe/Tiraspol) decided not to split from the rest of Moldova after
4751  all, and consequently that zone has been removed (again) and reinstated
4752  in the "backward" file as a link to Europe/Chisinau.   And third, the
4753  end date for Fiji's summer time this summer was moved forward from the
4754  earlier planned Feb 26, to Jan 22.
4755
4756  Apart from that, Moldova (MD) returns to a single entry in zone.tab
4757  (and the incorrect syntax that was in the 2011m version of that file
4758  is so fixed - it would have been fixed in a different way had this
4759  change not happened - that's the "missing" sccs version id).
4760
4761
4762Release data2011m - 2011-10-24 21:42:16 +0700
4763
4764  In particular, the typos in comments in the data (2011-11-17 should have
4765  been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
4766  Tim Parenti noted) have been fixed, and the change for Ukraine has been
4767  made in all 4 Ukrainian zones, rather than just Europe/Kiev
4768  (again, thanks to Tim Parenti, and also Denys Gavrysh).
4769
4770  In addition, I added Europe/Tiraspol to zone.tab.
4771
4772  This time, all the files have new version numbers...  (including the files
4773  otherwise unchanged in 2011m that were changed in 2011l but didn't get new
4774  version numbers there...)
4775
4776
4777Release data2011l - 2011-10-10 11:15:43 +0700
4778
4779  There are just 2 changes that cause different generated tzdata files from
4780  zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
4781  is included, but commented out.  Compared with the diff I sent out last week,
4782  this version also includes attributions for the sources for the changes
4783  (in much the same format as ado used, but the html tags have not been
4784  checked, verified, or used in any way at all, so if there are errors there,
4785  please let me know.)
4786
4787
4788Release data2011k - 2011-09-20 17:54:03 -0400
4789
4790  [not summarized]
4791
4792
4793Release data2011j - 2011-09-12 09:22:49 -0400
4794
4795  (contemporary changes for Samoa; past changes for Kenya, Uganda, and
4796  Tanzania); there are also two spelling corrections to comments in
4797  the australasia file (with thanks to Christos Zoulas).
4798
4799
4800Release 2011i - 2011-08-29 05:56:32 -0400
4801
4802  [not summarized]
4803
4804
4805Release data2011h - 2011-06-15 18:41:48 -0400
4806
4807  Russia and Curaçao changes
4808
4809
4810Release 2011g - 2011-04-25 09:07:22 -0400
4811
4812  update the rules for Egypt to reflect its abandonment of DST this year
4813
4814
4815Release 2011f - 2011-04-06 17:14:53 -0400
4816
4817  [not summarized]
4818
4819
4820Release 2011e - 2011-03-31 16:04:38 -0400
4821
4822  Morocco, Chile, and tz-link changes
4823
4824
4825Release 2011d - 2011-03-14 09:18:01 -0400
4826
4827  changes that impact present-day timestamps in Cuba, Samoa, and Turkey
4828
4829
4830Release 2011c - 2011-03-07 09:30:09 -0500
4831
4832  These do affect current timestamps in Chile and Annette Island, Canada.
4833
4834
4835Release 2011b - 2011-02-07 08:44:50 -0500
4836
4837  [not summarized]
4838
4839
4840Release 2011a - 2011-01-24 10:30:16 -0500
4841
4842  [not summarized]
4843
4844
4845Release data2010o - 2010-11-01 09:18:23 -0400
4846
4847  change to the end of DST in Fiji in 2011
4848
4849
4850Release 2010n - 2010-10-25 08:19:17 -0400
4851
4852  [not summarized]
4853
4854
4855Release 2010m - 2010-09-27 09:24:48 -0400
4856
4857  Hong Kong, Vostok, and zic.c changes
4858
4859
4860Release 2010l - 2010-08-16 06:57:25 -0400
4861
4862  [not summarized]
4863
4864
4865Release 2010k - 2010-07-26 10:42:27 -0400
4866
4867  [not summarized]
4868
4869
4870Release 2010j - 2010-05-10 09:07:48 -0400
4871
4872  changes for Bahía de Banderas and for version naming
4873
4874
4875Release data2010i - 2010-04-16 18:50:45 -0400
4876
4877  the end of DST in Morocco on 2010-08-08
4878
4879
4880Release data2010h - 2010-04-05 09:58:56 -0400
4881
4882  [not summarized]
4883
4884
4885Release data2010g - 2010-03-24 11:14:53 -0400
4886
4887  [not summarized]
4888
4889
4890Release 2010f - 2010-03-22 09:45:46 -0400
4891
4892  [not summarized]
4893
4894
4895Release data2010e - 2010-03-08 14:24:27 -0500
4896
4897  corrects the Dhaka bug found by Danvin Ruangchan
4898
4899
4900Release data2010d - 2010-03-06 07:26:01 -0500
4901
4902  [not summarized]
4903
4904
4905Release 2010c - 2010-03-01 09:20:58 -0500
4906
4907  changes including KRE's suggestion for earlier initialization of
4908  "goahead" and "goback" structure elements
4909
4910
4911Release code2010a - 2010-02-16 10:40:04 -0500
4912
4913  [not summarized]
4914
4915
4916Release data2010b - 2010-01-20 12:37:01 -0500
4917
4918  Mexico changes
4919
4920
4921Release data2010a - 2010-01-18 08:30:04 -0500
4922
4923  changes to Dhaka
4924
4925
4926Release data2009u - 2009-12-26 08:32:28 -0500
4927
4928  changes to DST in Bangladesh
4929
4930
4931Release 2009t - 2009-12-21 13:24:27 -0500
4932
4933  [not summarized]
4934
4935
4936Release data2009s - 2009-11-14 10:26:32 -0500
4937
4938  (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
4939
4940
4941Release 2009r - 2009-11-09 10:10:31 -0500
4942
4943  "antarctica" and "tz-link.htm" changes
4944
4945
4946Release 2009q - 2009-11-02 09:12:40 -0500
4947
4948  with two corrections as reported by Eric Muller and Philip Newton
4949
4950
4951Release data2009p - 2009-10-23 15:05:27 -0400
4952
4953  Argentina (including San Luis) changes (with the correction from
4954  Mariano Absatz)
4955
4956
4957Release data2009o - 2009-10-14 16:49:38 -0400
4958
4959  Samoa (commentary only), Pakistan, and Bangladesh changes
4960
4961
4962Release data2009n - 2009-09-22 15:13:38 -0400
4963
4964  added commentary for Argentina and a change to the end of DST in
4965  2009 in Pakistan
4966
4967
4968Release data2009m - 2009-09-03 10:23:43 -0400
4969
4970  Samoa and Palestine changes
4971
4972
4973Release data2009l - 2009-08-14 09:13:07 -0400
4974
4975  Samoa (comments only) and Egypt
4976
4977
4978Release 2009k - 2009-07-20 09:46:08 -0400
4979
4980  [not summarized]
4981
4982
4983Release data2009j - 2009-06-15 06:43:59 -0400
4984
4985  Bangladesh change (with a short turnaround since the DST change is
4986  impending)
4987
4988
4989Release 2009i - 2009-06-08 09:21:22 -0400
4990
4991  updating for DST in Bangladesh this year
4992
4993
4994Release 2009h - 2009-05-26 09:19:14 -0400
4995
4996  [not summarized]
4997
4998
4999Release data2009g - 2009-04-20 16:34:07 -0400
5000
5001  Cairo
5002
5003
5004Release data2009f - 2009-04-10 11:00:52 -0400
5005
5006  correct DST in Pakistan
5007
5008
5009Release 2009e - 2009-04-06 09:08:11 -0400
5010
5011  [not summarized]
5012
5013
5014Release 2009d - 2009-03-23 09:38:12 -0400
5015
5016  Morocco, Tunisia, Argentina, and American Astronomical Society changes
5017
5018
5019Release data2009c - 2009-03-16 09:47:51 -0400
5020
5021  change to the start of Cuban DST
5022
5023
5024Release 2009b - 2009-02-09 11:15:22 -0500
5025
5026  [not summarized]
5027
5028
5029Release 2009a - 2009-01-21 10:09:39 -0500
5030
5031  [not summarized]
5032
5033
5034Release data2008i - 2008-10-21 12:10:25 -0400
5035
5036  southamerica and zone.tab files, with Argentina DST rule changes and
5037  United States zone reordering and recommenting
5038
5039
5040Release 2008h - 2008-10-13 07:33:56 -0400
5041
5042  [not summarized]
5043
5044
5045Release 2008g - 2008-10-06 09:03:18 -0400
5046
5047  Fix a broken HTML anchor and update Brazil's DST transitions;
5048  there's also a slight reordering of information in tz-art.htm.
5049
5050
5051Release data2008f - 2008-09-09 22:33:26 -0400
5052
5053  [not summarized]
5054
5055
5056Release 2008e - 2008-07-28 14:11:17 -0400
5057
5058  changes by Arthur David Olson and Jesper Nørgaard Welen
5059
5060
5061Release data2008d - 2008-07-07 09:51:38 -0400
5062
5063  changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
5064
5065
5066Release data2008c - 2008-05-19 17:48:03 -0400
5067
5068  Pakistan, Morocco, and Mongolia
5069
5070
5071Release data2008b - 2008-03-24 08:30:59 -0400
5072
5073  including renaming Asia/Calcutta to Asia/Kolkata, with a backward
5074  link provided
5075
5076
5077Release 2008a - 2008-03-08 05:42:16 -0500
5078
5079  [not summarized]
5080
5081
5082Release 2007k - 2007-12-31 10:25:22 -0500
5083
5084  most importantly, changes to the "southamerica" file based on
5085  Argentina's readoption of daylight saving time
5086
5087
5088Release 2007j - 2007-12-03 09:51:01 -0500
5089
5090  1. eliminate the "P" (parameter) macro;
5091
5092  2. the "noncontroversial" changes circulated on the time zone
5093  mailing list (less the changes to "logwtmp.c");
5094
5095  3. eliminate "too many transition" errors when "min" is used in time
5096  zone rules;
5097
5098  4. changes by Paul Eggert (including updated information for Venezuela).
5099
5100
5101Release data2007i - 2007-10-30 10:28:11 -0400
5102
5103  changes for Cuba and Syria
5104
5105
5106Release 2007h - 2007-10-01 10:05:51 -0400
5107
5108  changes by Paul Eggert, as well as an updated link to the ICU
5109  project in tz-link.htm
5110
5111
5112Release 2007g - 2007-08-20 10:47:59 -0400
5113
5114  changes by Paul Eggert
5115
5116  The "leapseconds" file has been updated to incorporate the most
5117  recent International Earth Rotation and Reference Systems Service
5118  (IERS) bulletin.
5119
5120  There's an addition to tz-art.htm regarding the television show "Medium".
5121
5122
5123Release 2007f - 2007-05-07 10:46:46 -0400
5124
5125  changes by Paul Eggert (including Haiti, Turks and Caicos, and New
5126  Zealand)
5127
5128  changes to zic.c to allow hour values greater than 24 (along with
5129  Paul's improved time value overflow checking)
5130
5131
5132Release 2007e - 2007-04-02 10:11:52 -0400
5133
5134  Syria and Honduras changes by Paul Eggert
5135
5136  zic.c variable renaming changes by Arthur David Olson
5137
5138
5139Release 2007d - 2007-03-20 08:48:30 -0400
5140
5141  changes by Paul Eggert
5142
5143  the elimination of white space at the ends of lines
5144
5145
5146Release 2007c - 2007-02-26 09:09:37 -0500
5147
5148  changes by Paul Eggert
5149
5150
5151Release 2007b - 2007-02-12 09:34:20 -0500
5152
5153  Paul Eggert's proposed change to the quotation handling logic in zic.c.
5154
5155  changes to the commentary in "leapseconds" reflecting the IERS
5156  announcement that there is to be no positive leap second at the end
5157  of June 2007.
5158
5159
5160Release 2007a - 2007-01-08 12:28:29 -0500
5161
5162  changes by Paul Eggert
5163
5164  Derick Rethans's Asmara change
5165
5166  Oscar van Vlijmen's Easter Island local mean time change
5167
5168  symbolic link changes
5169
5170
5171Release 2006p - 2006-11-27 08:54:27 -0500
5172
5173  changes by Paul Eggert
5174
5175
5176Release 2006o - 2006-11-06 09:18:07 -0500
5177
5178  changes by Paul Eggert
5179
5180
5181Release 2006n - 2006-10-10 11:32:06 -0400
5182
5183  changes by Paul Eggert
5184
5185
5186Release 2006m - 2006-10-02 15:32:35 -0400
5187
5188  changes for Uruguay, Palestine, and Egypt by Paul Eggert
5189
5190  (minimalist) changes to zic.8 to clarify "until" information
5191
5192
5193Release data2006l - 2006-09-18 12:58:11 -0400
5194
5195  Paul's best-effort work on this coming weekend's Egypt time change
5196
5197
5198Release 2006k - 2006-08-28 12:19:09 -0400
5199
5200  changes by Paul Eggert
5201
5202
5203Release 2006j - 2006-08-21 09:56:32 -0400
5204
5205  changes by Paul Eggert
5206
5207
5208Release code2006i - 2006-08-07 12:30:55 -0400
5209
5210  localtime.c fixes
5211
5212  Ken Pizzini's conversion script
5213
5214
5215Release code2006h - 2006-07-24 09:19:37 -0400
5216
5217  adds public domain notices to four files
5218
5219  includes a fix for transition times being off by a second
5220
5221  adds a new recording to the "arts" file (information courtesy Colin Bowern)
5222
5223
5224Release 2006g - 2006-05-08 17:18:09 -0400
5225
5226  northamerica changes by Paul Eggert
5227
5228
5229Release 2006f - 2006-05-01 11:46:00 -0400
5230
5231  a missing version number problem is fixed (with thanks to Bradley
5232  White for catching the problem)
5233
5234
5235Release 2006d - 2006-04-17 14:33:43 -0400
5236
5237  changes by Paul Eggert
5238
5239  added new items to tz-arts.htm that were found by Paul
5240
5241
5242Release 2006c - 2006-04-03 10:09:32 -0400
5243
5244  two sets of data changes by Paul Eggert
5245
5246  a fencepost error fix in zic.c
5247
5248  changes to zic.c and the "europe" file to minimize differences
5249  between output produced by the old 32-bit zic and the new 64-bit
5250  version
5251
5252
5253Release 2006b - 2006-02-20 10:08:18 -0500
5254  [tz32code2006b + tz64code2006b + tzdata2006b]
5255
5256  64-bit code
5257
5258  All SCCS IDs were bumped to "8.1" for this release.
5259
5260
5261Release 2006a - 2006-01-30 08:59:31 -0500
5262
5263  changes by Paul Eggert (in particular, Indiana time zone moves)
5264
5265  an addition to the zic manual page to describe how special-case
5266  transitions are handled
5267
5268
5269Release 2005r - 2005-12-27 09:27:13 -0500
5270
5271  Canadian changes by Paul Eggert
5272
5273  They also add "<pre>" directives to time zone data files and reflect
5274  changes to warning message logic in "zdump.c" (but with calls to
5275  "gettext" kept unbundled at the suggestion of Ken Pizzini).
5276
5277
5278Release 2005q - 2005-12-13 09:17:09 -0500
5279
5280  Nothing earth-shaking here:
5281	1.  Electronic mail addresses have been removed.
5282	2.  Casts of the return value of exit have been removed.
5283	3.  Casts of the argument of is.* macros have been added.
5284	4.  Indentation in one section of zic.c has been fixed.
5285	5.  References to dead URLs in the data files have been dealt with.
5286
5287
5288Release 2005p - 2005-12-05 10:30:53 -0500
5289
5290  "systemv", "tz-link.htm", and "zdump.c" changes
5291  (less the casts of arguments to the is* macros)
5292
5293
5294Release 2005o - 2005-11-28 10:55:26 -0500
5295
5296  Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
5297
5298  zdump.c lint fixes by Arthur David Olson
5299
5300
5301Release 2005n - 2005-10-03 09:44:09 -0400
5302
5303  changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
5304  et al. changes)
5305
5306
5307Release 2005m - 2005-08-29 12:15:40 -0400
5308
5309  changes by Paul Eggert (with a small tweak to the tz-art change)
5310
5311  a declaration of an unused variable has been removed from zdump.c
5312
5313
5314Release 2005l - 2005-08-22 12:06:39 -0400
5315
5316  changes by Paul Eggert
5317
5318  overflow/underflow checks by Arthur David Olson, minus changes to
5319  the "Theory" file about the pending addition of 64-bit data (I grow
5320  less confident of the changes being accepted with each passing day,
5321  and the changes no longer increase the data files nine-fold--there's
5322  less than a doubling in size by my local Sun's reckoning)
5323
5324
5325Release 2005k - 2005-07-14 14:14:24 -0400
5326
5327  The "leapseconds" file has been edited to reflect the recently
5328  announced leap second at the end of 2005.
5329
5330  I've also deleted electronic mail addresses from the files as an
5331  anti-spam measure.
5332
5333
5334Release 2005j - 2005-06-13 14:34:13 -0400
5335
5336  These reflect changes to limit the length of time zone abbreviations
5337  and the characters used in those abbreviations.
5338
5339  There are also changes to handle POSIX-style "quoted" timezone
5340  environment variables.
5341
5342  The changes were circulated on the time zone mailing list; the only
5343  change since then was the removal of a couple of minimum-length of
5344  abbreviation checks.
5345
5346
5347Release data2005i - 2005-04-21 15:04:16 -0400
5348
5349  changes (most importantly to Nicaragua and Haiti) by Paul Eggert
5350
5351
5352Release 2005h - 2005-04-04 11:24:47 -0400
5353
5354  changes by Paul Eggert
5355
5356  minor changes to Makefile and zdump.c to produce more useful output
5357  when doing a "make typecheck"
5358
5359
5360Release 2005g - 2005-03-14 10:11:21 -0500
5361
5362  changes by Paul Eggert (a change to current DST rules in Uruguay and
5363  an update to a link to time zone software)
5364
5365
5366Release 2005f - 2005-03-01 08:45:32 -0500
5367
5368  data and documentation changes by Paul Eggert
5369
5370
5371Release 2005e - 2005-02-10 15:59:44 -0500
5372
5373  [not summarized]
5374
5375
5376Release code2005d - 2005-01-31 09:21:47 -0500
5377
5378  make zic complain about links to links if the -v flag is used
5379
5380  have "make public" do more code checking
5381
5382  add an include to "localtime.c" for the benefit of gcc systems
5383
5384
5385Release 2005c - 2005-01-17 18:36:29 -0500
5386
5387  get better results when mktime runs on a system where time_t is double
5388
5389  changes to the data files (most importantly to Paraguay)
5390
5391
5392Release 2005b - 2005-01-10 09:19:54 -0500
5393
5394  Get localtime and gmtime working on systems with exotic time_t types.
5395
5396  Update the leap second commentary in the "leapseconds" file.
5397
5398
5399Release 2005a - 2005-01-01 13:13:44 -0500
5400
5401  [not summarized]
5402
5403
5404Release code2004i - 2004-12-14 13:42:58 -0500
5405
5406  Deal with systems where time_t is unsigned.
5407
5408
5409Release code2004h - 2004-12-07 11:40:18 -0500
5410
5411  64-bit-time_t changes
5412
5413
5414Release 2004g - 2004-11-02 09:06:01 -0500
5415
5416  update to Cuba (taking effect this weekend)
5417
5418  other changes by Paul Eggert
5419
5420  correction of the spelling of Oslo
5421
5422  changed versions of difftime.c and private.h
5423
5424
5425Release code2004f - 2004-10-21 10:25:22 -0400
5426
5427  Cope with wide-ranging tm_year values.
5428
5429
5430Release 2004e - 2004-10-11 14:47:21 -0400
5431
5432  Brazil/Argentina/Israel changes by Paul Eggert
5433
5434  changes to tz-link.htm by Paul
5435
5436  one small fix to Makefile
5437
5438
5439Release 2004d - 2004-09-22 08:27:29 -0400
5440
5441  Avoid overflow problems when TM_YEAR_BASE is added to an integer.
5442
5443
5444Release 2004c - 2004-08-11 12:06:26 -0400
5445
5446  asctime-related changes
5447
5448  (variants of) some of the documentation changes suggested by Paul Eggert
5449
5450
5451Release 2004b - 2004-07-19 14:33:35 -0400
5452
5453  data changes by Paul Eggert - most importantly, updates for Argentina
5454
5455
5456Release 2004a - 2004-05-27 12:00:47 -0400
5457
5458  changes by Paul Eggert
5459
5460  Handle DST transitions that occur at the end of a month in some
5461  years but at the start of the following month in other years.
5462
5463  Add a copy of the correspondence that's the basis for claims about
5464  DST in the Navajo Nation.
5465
5466
5467Release 2003e - 2003-12-15 09:36:47 -0500
5468
5469  changes by Arthur David Olson (primarily code changes)
5470
5471  changes by Paul Eggert (primarily data changes)
5472
5473  minor changes to "Makefile" and "northamerica" (in the latter case,
5474  optimization of the "Toronto" rules)
5475
5476
5477Release 2003d - 2003-10-06 09:34:44 -0400
5478
5479  changes by Paul Eggert
5480
5481
5482Release 2003c - 2003-09-16 10:47:05 -0400
5483
5484  Fix bad returns in zic.c's inleap function.
5485  Thanks to Bradley White for catching the problem!
5486
5487
5488Release 2003b - 2003-09-16 07:13:44 -0400
5489
5490  Add a "--version" option (and documentation) to the zic and zdump commands.
5491
5492  changes to overflow/underflow checking in zic
5493
5494  a localtime typo fix.
5495
5496  Update the leapseconds and tz-art.htm files.
5497
5498
5499Release 2003a - 2003-03-24 09:30:54 -0500
5500
5501  changes by Paul Eggert
5502
5503  a few additions and modifications to the tz-art.htm file
5504
5505
5506Release 2002d - 2002-10-15 13:12:42 -0400
5507
5508  changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
5509
5510  There's also a new time zone quote in "tz-art.htm".
5511
5512
5513Release 2002c - 2002-04-04 11:55:20 -0500
5514
5515  changes by Paul Eggert
5516
5517  Change zic.c to avoid creating symlinks to files that don't exist.
5518
5519
5520Release 2002b - 2002-01-28 12:56:03 -0500
5521
5522  [These change notes are for Release 2002a, which was corrupted.
5523  2002b was a corrected version of 2002a.]
5524
5525  changes by Paul Eggert
5526
5527  Update the "leapseconds" file to note that there'll be no leap
5528  second at the end of June, 2002.
5529
5530  Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
5531
5532  Change to "difftime.c" to avoid sizeof problems.
5533
5534
5535Release 2001d - 2001-10-09 13:31:32 -0400
5536
5537  changes by Paul Eggert
5538
5539
5540Release 2001c - 2001-06-05 13:59:55 -0400
5541
5542  changes by Paul Eggert and Andrew Brown
5543
5544
5545Release 2001b - 2001-04-05 16:44:38 -0400
5546
5547  changes by Paul Eggert (modulo jnorgard's typo fix)
5548
5549  tz-art.htm has been HTMLified.
5550
5551
5552Release 2001a - 2001-03-13 12:57:44 -0500
5553
5554  changes by Paul Eggert
5555
5556  An addition to the "leapseconds" file: comments with the text of the
5557  latest IERS leap second notice.
5558
5559  Trailing white space has been removed from data file lines, and
5560  repeated spaces in "Rule Jordan" lines in the "asia" file have been
5561  converted to tabs.
5562
5563
5564Release 2000h - 2000-12-14 15:33:38 -0500
5565
5566  changes by Paul Eggert
5567
5568  one typo fix in the "art" file
5569
5570  With providence, this is the last update of the millennium.
5571
5572
5573Release 2000g - 2000-10-10 11:35:22 -0400
5574
5575  changes by Paul Eggert
5576
5577  correction of John Mackin's name submitted by Robert Elz
5578
5579  Garry Shandling's Daylight Saving Time joke (!?!) from the recent
5580  Emmy Awards broadcast.
5581
5582
5583Release 2000f - 2000-08-10 09:31:58 -0400
5584
5585  changes by Paul Eggert
5586
5587  Added information in "tz-art.htm" on a Seinfeld reference to DST.
5588
5589  Error checking and messages in the "yearistype" script have been
5590  improved.
5591
5592
5593Release 2000e - 2000-07-31 09:27:54 -0400
5594
5595  data changes by Paul Eggert
5596
5597  a change to the default value of the defined constant HAVE_STRERROR
5598
5599  the addition of a Dave Barry quote on DST to the tz-arts file
5600
5601
5602Release 2000d - 2000-04-20 15:43:04 -0400
5603
5604  changes to the documentation and code of strftime for C99 conformance
5605
5606  a bug fix for date.c
5607
5608  These are based on (though modified from) changes by Paul Eggert.
5609
5610
5611Release 2000c - 2000-03-04 10:31:43 -0500
5612
5613  changes by Paul Eggert
5614
5615
5616Release 2000b - 2000-02-21 12:16:29 -0500
5617
5618  changes by Paul Eggert and Joseph Myers
5619
5620  modest tweaks to the tz-art.htm and tz-link.htm files
5621
5622
5623Release 2000a - 2000-01-18 09:21:26 -0500
5624
5625  changes by Paul Eggert
5626
5627  The two hypertext documents have also been renamed.
5628
5629
5630Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
5631
5632  Paul Eggert's changes
5633
5634  additions to the "zic" manual page and the "Arts.htm" file
5635
5636
5637Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
5638
5639  [not summarized]
5640
5641
5642Release data1999h - 1999-10-07 03:50:29 -0400
5643
5644  changes by Paul Eggert to "europe" (most importantly, fixing
5645  Lithuania and Estonia)
5646
5647
5648Release 1999g - 1999-09-28 11:06:18 -0400
5649
5650  data changes by Paul Eggert (most importantly, the change for
5651  Lebanon that buys correctness for this coming Sunday)
5652
5653  The "code" file contains changes to "Makefile" and "checktab.awk" to
5654  allow better checking of time zone files before they are published.
5655
5656
5657Release 1999f - 1999-09-23 09:48:14 -0400
5658
5659  changes by Arthur David Olson and Paul Eggert
5660
5661
5662Release 1999e - 1999-08-17 15:20:54 -0400
5663
5664  changes circulated by Paul Eggert, although the change to handling
5665  of DST-specifying timezone names has been commented out for now
5666  (search for "XXX" in "localtime.c" for details).  These files also
5667  do not make any changes to the start of DST in Brazil.
5668
5669  In addition to Paul's changes, there are updates to "Arts.htm" and
5670  cleanups of URLs.
5671
5672
5673Release 1999d - 1999-03-30 11:31:07 -0500
5674
5675  changes by Paul Eggert
5676
5677  The Makefile's "make public" rule has also been changed to do a test
5678  compile of each individual time zone data file (which should help
5679  avoid problems such as the one we had with Nicosia).
5680
5681
5682Release 1999c - 1999-03-25 09:47:47 -0500
5683
5684  changes by Paul Eggert, most importantly the change for Chile.
5685
5686
5687Release 1999b - 1999-02-01 17:51:44 -0500
5688
5689  changes by Paul Eggert
5690
5691  code changes (suggested by Mani Varadarajan, mani at be.com) for
5692  correct handling of symbolic links when building using a relative directory
5693
5694  code changes to generate correct messages for failed links
5695
5696  updates to the URLs in Arts.htm
5697
5698
5699Release 1999a - 1999-01-19 16:20:29 -0500
5700
5701  error message internationalizations and corrections in zic.c and
5702  zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
5703  to whom thanks!)
5704
5705
5706Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
5707
5708  changes for Brazil, Chile, and Germany
5709
5710  support for use of "24:00" in the input files for the time zone compiler
5711
5712
5713Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
5714
5715  changes by Paul Eggert
5716
5717  correction to a define in the "private.h" file
5718
5719
5720Release data1998g - 1998-08-11 03:28:35 -0000
5721  [tzdata1998g.tar.gz is missing!]
5722
5723  Lithuanian change provided by mgedmin at pub.osf.it
5724
5725  Move creation of the GMT link with Etc/GMT to "etcetera" (from
5726  "backward") to ensure that the GMT file is created even where folks
5727  don't want the "backward" links (as suggested by Paul Eggert).
5728
5729
5730Release data1998f - 1998-07-20 13:50:00 -0000
5731  [tzdata1998f.tar.gz is missing!]
5732
5733  Update the "leapseconds" file to include the newly announced
5734  insertion at the end of 1998.
5735
5736
5737Release code1998f - 1998-06-01 10:18:31 -0400
5738
5739  addition to localtime.c by Guy Harris
5740
5741
5742Release 1998e - 1998-05-28 09:56:26 -0400
5743
5744  The Makefile is changed to produce zoneinfo-posix rather than
5745  zoneinfo/posix, and to produce zoneinfo-leaps rather than
5746  zoneinfo/right.
5747
5748  data changes by Paul Eggert
5749
5750  changes from Guy Harris to provide asctime_r and ctime_r
5751
5752  A usno1998 file (substantially identical to usno1997) has been added.
5753
5754
5755Release 1998d - 1998-05-14 11:58:34 -0400
5756
5757  changes to comments (in particular, elimination of references to CIA maps).
5758  "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
5759  where changes occur.
5760
5761
5762Release 1998c - 1998-02-28 12:32:26 -0500
5763
5764  changes by Paul Eggert (save the "French correction," on which I'll
5765  wait for the dust to settle)
5766
5767  symlink changes
5768
5769  changes and additions to Arts.htm
5770
5771
5772Release 1998b - 1998-01-17 14:31:51 -0500
5773
5774  URL cleanups and additions
5775
5776
5777Release 1998a - 1998-01-13 12:37:35 -0500
5778
5779  changes by Paul Eggert
5780
5781
5782Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
5783
5784  changes by Paul Eggert, with minor modifications from Arthur David
5785  Olson to make the files more browser friendly
5786
5787
5788Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
5789
5790  minor changes to put "TZif" at the start of each timezone information file
5791
5792  a rule has also been added to the Makefile so you can
5793	make zones
5794  to just recompile the zone information files (rather than doing a
5795  full "make install" with its other effects).
5796
5797
5798Release data1997i - 1997-10-07 08:45:38 -0400
5799
5800  changes to Africa by Paul Eggert
5801
5802
5803Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
5804
5805  corrections for Uruguay (and other locations)
5806
5807  Arthur David Olson's simple-minded fix allowing mktime to both
5808  correctly handle leap seconds and correctly handle tm_sec values
5809  upon which arithmetic has been performed.
5810
5811
5812Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
5813
5814  Paul Eggert's updates
5815
5816  a small change to a function prototype;
5817
5818  "Music" has been renamed "Arts.htm", HTMLified, and augmented to
5819  include information on Around the World in Eighty Days.
5820
5821
5822Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
5823
5824  fixes to zic's error handling
5825
5826  changes inspired by the item circulated on Slovenia
5827
5828  The description of Web resources has been HTMLified for browsing
5829  convenience.
5830
5831  A new piece of tz-related music has been added to the "Music" file.
5832
5833
5834Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
5835
5836  Paul Eggert's latest suggestions
5837
5838
5839Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
5840
5841  changes to "zic.c" to correct performance of the "-s" option
5842
5843  a new file "usno1997"
5844
5845
5846Release data1997c - 1997-03-04 09:58:18 -0500
5847
5848  changes in Israel
5849
5850
5851Release 1997b - 1997-02-27 18:34:19 -0500
5852
5853  The data file incorporates the 1997 leap second.
5854
5855  The code file incorporates Arthur David Olson's take on the
5856  zic/multiprocessor/directory-creation situation.
5857
5858
5859Release 1997a - 1997-01-21 09:11:10 -0500
5860
5861  Paul Eggert's Antarctica (and other changes)
5862
5863  Arthur David Olson finessed the "getopt" issue by checking against
5864  both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
5865  is returned while SunOS 5.5's manual says EOF is returned).
5866
5867
5868Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
5869
5870  Paul Eggert's latest changes
5871
5872
5873Release code1996n - 1996-12-16 09:42:02 -0500
5874
5875  link snapping fix from Bruce Evans (via Garrett Wollman)
5876
5877
5878Release data1996m - 1996-11-24 02:37:34 -0000
5879  [tzdata1996m.tar.gz is missing!]
5880
5881  Paul Eggert's batch of changes
5882
5883
5884Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
5885
5886  No functional changes here; the files have simply been changed to
5887  make more use of ISO style dates in comments. The names of the above
5888  files now include the year in full.
5889
5890
5891Release code96l - 1996-09-08 17:12:20 -0400
5892
5893  tzcode96k was missing a couple of pieces.
5894
5895
5896Release 96k - 1996-09-08 16:06:22 -0400
5897
5898  the latest round of changes from Paul Eggert
5899
5900  the recent Year 2000 material
5901
5902
5903Release code96j - 1996-07-30 13:18:53 -0400
5904
5905  Set sp->typecnt as suggested by Timothy Patrick Murphy.
5906
5907
5908Release code96i - 1996-07-27 20:11:35 -0400
5909
5910  Paul's suggested patch for strftime %V week numbers
5911
5912
5913Release data96i - 1996-07-01 18:13:04 -0400
5914
5915  "northamerica" and "europe" changes by Paul Eggert
5916
5917
5918Release code96h - 1996-06-05 08:02:21 -0400
5919
5920  fix for handling transitions specified in Universal Time
5921
5922  Some "public domain" notices have also been added.
5923
5924
5925Release code96g - 1996-05-16 14:00:26 -0400
5926
5927  fix for the simultaneous-DST-and-zone-change challenge
5928
5929
5930Release data96h - 1996-05-09 17:40:51 -0400
5931
5932  changes by Paul Eggert
5933
5934
5935Release code96f-data96g - 1996-05-03 03:09:59 -0000
5936  [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
5937
5938  The changes get us some of the way to fixing the problems noted in Paul
5939  Eggert's letter yesterday (in addition to a few others).  The approach
5940  has been to make zic a bit smarter about figuring out what time zone
5941  abbreviations apply just after the time specified in the "UNTIL" part
5942  of a zone line.  Putting the smarts in zic means avoiding having
5943  transition times show up in both "Zone" lines and "Rule" lines, which
5944  in turn avoids multiple transition time entries in time zone files.
5945  (This also makes the zic input files such as "europe" a bit shorter and
5946  should ease maintenance.)
5947
5948
5949Release data96f - 1996-04-19 19:20:03 -0000
5950  [tzdata96f.tar.gz is missing!]
5951
5952  The only changes are to the "northamerica" file; the time zone
5953  abbreviation for Denver is corrected to MST (and MDT), and the
5954  comments for Mexico have been updated.
5955
5956
5957Release data96e - 1996-03-19 17:37:26 -0500
5958
5959  Proposals by Paul Eggert, in particular the Portugal change that
5960  comes into play at the end of this month.
5961
5962
5963Release data96d - 1996-03-18 20:49:39 -0500
5964
5965  [not summarized]
5966
5967
5968Release code96e - 1996-02-29 15:43:27 -0000
5969  [tzcode96e.tar.gz is missing!]
5970
5971  internationalization changes and the fix to the documentation for strftime
5972
5973
5974Release code96d-data96c - 1996-02-12 11:05:27 -0500
5975
5976  The "code" file simply updates Bob Kridle's electronic address.
5977
5978  The "data" file updates rules for Mexico.
5979
5980
5981Release data96b - 1996-01-27 15:44:42 -0500
5982
5983  Kiribati change
5984
5985
5986Release code96c - 1996-01-16 16:58:15 -0500
5987
5988  leap-year streamlining and binary-search changes
5989
5990  fix to newctime.3
5991
5992
5993Release code96b - 1996-01-10 20:42:39 -0500
5994
5995  fixes and enhancements from Paul Eggert, including code that
5996  emulates the behavior of recent versions of the SunOS "date"
5997  command.
5998
5999
6000Release 96a - 1996-01-06 09:08:24 -0500
6001
6002  Israel updates
6003
6004  fixes to strftime.c for correct ISO 8601 week number generation,
6005  plus support for two new formats ('G' and 'g') to give ISO 8601 year
6006  numbers (which are not necessarily the same as calendar year numbers)
6007
6008
6009Release code95i-data95m - 1995-12-21 12:46:47 -0500
6010
6011  The latest revisions from Paul Eggert are included, the usno1995
6012  file has been updated, and a new file ("WWW") covering useful URLs
6013  has been added.
6014
6015
6016Release code95h-data95l - 1995-12-19 18:10:12 -0500
6017
6018  A simplification of a macro definition, a change to data for Sudan,
6019  and (for last minute shoppers) notes in the "Music" file on the CD
6020  "Old Man Time".
6021
6022
6023Release code95g-data95k - 1995-10-30 10:32:47 -0500
6024
6025  (slightly reformatted) 8-bit-clean proposed patch
6026
6027  minor patch: US/Eastern -> America/New_York
6028
6029  snapshot of the USNO's latest data ("usno1995")
6030
6031  some other minor cleanups
6032
6033
6034Release code95f-data95j - 1995-10-28 21:01:34 -0000
6035  [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
6036
6037  European cleanups
6038
6039  support for 64-bit time_t's
6040
6041  optimization in localtime.c
6042
6043
6044Release code95e - 1995-10-13 13:23:57 -0400
6045
6046  the mktime change to scan from future to past when trying to find time zone
6047  offsets
6048
6049
6050Release data95i - 1995-09-26 10:43:26 -0400
6051
6052  For Canada/Central, guess that the Sun customer's "one week too
6053  early" was just a approximation, and the true error is one month
6054  too early.  This is consistent with the rest of Canada.
6055
6056
6057Release data95h - 1995-09-21 11:26:48 -0400
6058
6059  latest changes from Paul Eggert
6060
6061
6062Release code95d - 1995-09-14 11:14:45 -0400
6063
6064  the addition of a "Music" file, which documents four recorded
6065  versions of the tune "Save That Time".
6066
6067
6068Release data95g - 1995-09-01 17:21:36 -0400
6069
6070  "yearistype" correction
6071
6072
6073Release data95f - 1995-08-28 20:46:56 -0400
6074
6075  Paul Eggert's change to the australasia file
6076
6077
6078Release data95e - 1995-07-08 18:02:34 -0400
6079
6080  The only change is a leap second at the end of this year.
6081  Thanks to Bradley White for forwarding news on the leap second.
6082
6083
6084Release data95d - 1995-07-03 13:26:22 -0400
6085
6086  Paul Eggert's changes
6087
6088
6089Release data95c - 1995-07-02 19:19:28 -0400
6090
6091  changes to "asia", "backward", "europe", and "southamerica"
6092  (read: northamericacentrics need not apply)
6093
6094
6095Release code95c - 1995-03-13 14:00:46 -0500
6096
6097  one-line fix for sign extension problems in detzcode
6098
6099
6100Release 95b - 1995-03-04 11:22:38 -0500
6101
6102  Minor changes in both:
6103
6104  The "code" file contains a workaround for the lack of "unistd.h" in
6105  Microsoft C++ version 7.
6106
6107  The "data" file contains a fixed "Link" for America/Shiprock.
6108
6109
6110Release 94h - 1994-12-10 12:51:14 -0500
6111
6112  The files:
6113
6114  *	incorporate the changes to "zdump" and "date" to make changes to
6115	the "TZ" environment variable permanent;
6116
6117  *	incorporate the table changes by Paul Eggert;
6118
6119  *	include (and document) support for universal time specifications in
6120	data files - but do not (yet) include use of this feature in the
6121	data files.
6122
6123  Think of this as "TZ Classic" - the software has been set up not to break if
6124  universal time shows up in its input, and data entries have been
6125  left as is so as not to break existing implementations.
6126
6127
6128Release data94f - 1994-08-20 12:56:09 -0400
6129
6130  (with thanks!) the latest data updates from Paul Eggert
6131
6132
6133Release data94e - 1994-06-04 13:13:53 -0400
6134
6135  [not summarized]
6136
6137
6138Release code94g - 1994-05-05 12:14:07 -0400
6139
6140  fix missing "optind.c" and a reference to it in the Makefile
6141
6142
6143Release code94f - 1994-05-05 13:00:33 -0000
6144  [tzcode94f.tar.gz is missing!]
6145
6146  changes to avoid overflow in difftime, as well as changes to cope
6147  with the 52/53 challenge in strftime
6148
6149
6150Release code94e - 1994-03-30 23:32:59 -0500
6151
6152  change for the benefit of PCTS
6153
6154
6155Release 94d - 1994-02-24 15:42:25 -0500
6156
6157  Avoid clashes with POSIX semantics for zones such as GMT+4.
6158
6159  Some other very minor housekeeping is also present.
6160
6161
6162Release code94c - 1994-02-10 08:52:40 -0500
6163
6164  Fix bug where mkdirs was broken unless you compile with
6165  -fwritable-strings (which is generally losing to do).
6166
6167
6168Release 94b - 1994-02-07 10:04:33 -0500
6169
6170  work by Paul Eggert who notes:
6171
6172  I found another book of time zone histories by E W Whitman; it's not
6173  as extensive as Shanks but has a few goodies of its own.  I used it
6174  to update the tables.  I also fixed some more as a result of
6175  correspondence with Adam David and Peter Ilieve, and move some stray
6176  links from 'europe' to 'backward'.  I corrected some scanning errors
6177  in usno1989.
6178
6179  As far as the code goes, I fixed zic to allow years in the range
6180  INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
6181  And I cleaned up the zic documentation a little bit.
6182
6183
6184Release data94a - 1994-02-03 08:58:54 -0500
6185
6186  It simply incorporates the recently announced leap second into the
6187  "leapseconds" file.
6188
6189
6190Release 93g - 1993-11-22 17:28:27 -0500
6191
6192  Paul Eggert has provided a good deal of historic information (based
6193  on Shanks), and there are some code changes to deal with the buglets
6194  that crawled out in dealing with the new information.
6195
6196
6197Release 93f - 1993-10-15 12:27:46 -0400
6198
6199  Paul Eggert's changes
6200
6201
6202Release 93e - 1993-09-05 21:21:44 -0400
6203
6204  This has updated data for Israel, England, and Kwajalein.  There's
6205  also an update to "zdump" to cope with Kwajalein's 24-hour jump.
6206  Thanks to Paul Eggert and Peter Ilieve for the changes.
6207
6208
6209Release 93d - 1993-06-17 23:34:17 -0400
6210
6211  new fix and new data on Israel
6212
6213
6214Release 93c - 1993-06-06 19:31:55 -0400
6215
6216  [not summarized]
6217
6218
6219Release 93b - 1993-02-02 14:53:58 -0500
6220
6221  updated "leapseconds" file
6222
6223
6224Release 93 - 1993-01-08 07:01:06 -0500
6225
6226  At kre's suggestion, the package has been split in two - a code piece
6227  (which also includes documentation) that's only of use to folks who
6228  want to recompile things and a data piece useful to anyone who can
6229  run "zic".
6230
6231  The new version has a few changes to the data files, a few
6232  portability changes, and an off-by-one fix (with thanks to
6233  Tom Karzes at deshaw.com for providing a description and a
6234  solution).
6235
6236
6237Release 92c - 1992-11-21 17:35:36 -0000
6238  [tz92c.tar.Z is missing!]
6239
6240  The fallout from the latest round of DST transitions.
6241
6242  There are changes for Portugal, Saskatchewan, and "Pacific-New";
6243  there's also a change to "zic.c" that makes it portable to more systems.
6244
6245
6246Release 92 - 1992-04-25 18:17:03 -0000
6247  [tz92.tar.Z is missing!]
6248
6249  By popular demand (well, at any rate, following a request by kre at munnari)
6250
6251
6252The 1989 update of the time zone package featured:
6253
6254  *	POSIXization (including interpretation of POSIX-style TZ environment
6255	variables, provided by Guy Harris),
6256  *	ANSIfication (including versions of "mktime" and "difftime"),
6257  *	SVIDulation (an "altzone" variable)
6258  *	MACHination (the "gtime" function)
6259  *	corrections to some time zone data (including corrections to the rules
6260	for Great Britain and New Zealand)
6261  *	reference data from the United States Naval Observatory for folks who
6262	want to do additional time zones
6263  *	and the 1989 data for Saudi Arabia.
6264
6265  (Since this code will be treated as "part of the implementation" in some
6266  places and as "part of the application" in others, there's no good way to
6267  name functions, such as timegm, that are not part of the proposed ANSI C
6268  standard; such functions have kept their old, underscore-free names in this
6269  update.)
6270
6271  And the "dysize" function has disappeared; it was present to allow
6272  compilation of the "date" command on old BSD systems, and a version of "date"
6273  is now provided in the package.  The "date" command is not created when you
6274  "make all" since it may lack options provided by the version distributed with
6275  your operating system, or may not interact with the system in the same way
6276  the native version does.
6277
6278  Since POSIX frowns on correct leap second handling, the default behavior of
6279  the "zic" command (in the absence of a "-L" option) has been changed to omit
6280  leap second information from its output files.
6281
6282
6283-----
6284Notes
6285
6286This file contains copies of the part of each release announcement
6287that talks about the changes in that release.  The text has been
6288adapted and reformatted for the purposes of this file.
6289
6290Traditionally a release R consists of a pair of tarball files,
6291tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
6292code2010a, data2012c) consist of just one or the other tarball, and a
6293few (e.g., code2012c-data2012d) have tarballs with mixed version
6294numbers.  Recent releases also come in an experimental format
6295consisting of a single tarball tzdb-R.tar.lz with extra data.
6296
6297Release timestamps are taken from the release's commit (for newer,
6298Git-based releases), from the newest file in the tarball (for older
6299releases, where this info is available) or from the email announcing
6300the release (if all else fails; these are marked with a time zone
6301abbreviation of -0000 and an "is missing!" comment).
6302
6303Earlier versions of the code and data were not announced on the tz
6304list and are not summarized here.
6305
6306This file is in the public domain.
6307
6308Local Variables:
6309coding: utf-8
6310End:
6311