xref: /freebsd/contrib/tzdata/NEWS (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
1News for the tz database
2
3Release 2024a - 2024-02-01 09:28:56 -0800
4
5  Briefly:
6    Kazakhstan unifies on UTC+5 beginning 2024-03-01.
7    Palestine springs forward a week later after Ramadan.
8    zic no longer pretends to support indefinite-past DST.
9    localtime no longer mishandles Ciudad Juárez in 2422.
10
11  Changes to future timestamps
12
13    Kazakhstan unifies on UTC+5.  This affects Asia/Almaty and
14    Asia/Qostanay which together represent the eastern portion of the
15    country that will transition from UTC+6 on 2024-03-01 at 00:00 to
16    join the western portion.  (Thanks to Zhanbolat Raimbekov.)
17
18    Palestine springs forward a week later than previously predicted
19    in 2024 and 2025.  (Thanks to Heba Hamad.)  Change spring-forward
20    predictions to the second Saturday after Ramadan, not the first;
21    this also affects other predictions starting in 2039.
22
23  Changes to past timestamps
24
25    Asia/Ho_Chi_Minh's 1955-07-01 transition occurred at 01:00
26    not 00:00.  (Thanks to Đoàn Trần Công Danh.)
27
28    From 1947 through 1949, Toronto's transitions occurred at 02:00
29    not 00:00.  (Thanks to Chris Walton.)
30
31    In 1911 Miquelon adopted standard time on June 15, not May 15.
32
33  Changes to code
34
35    The FROM and TO columns of Rule lines can no longer be "minimum"
36    or an abbreviation of "minimum", because TZif files do not support
37    DST rules that extend into the indefinite past - although these
38    rules were supported when TZif files had only 32-bit data, this
39    stopped working when 64-bit TZif files were introduced in 1995.
40    This should not be a problem for realistic data, since DST was
41    first used in the 20th century.  As a transition aid, FROM columns
42    like "minimum" are now diagnosed and then treated as if they were
43    the year 1900; this should suffice for TZif files on old systems
44    with only 32-bit time_t, and it is more compatible with bugs in
45    2023c-and-earlier localtime.c.  (Problem reported by Yoshito
46    Umaoka.)
47
48    localtime and related functions no longer mishandle some
49    timestamps that occur about 400 years after a switch to a time
50    zone with a DST schedule.  In 2023d data this problem was visible
51    for some timestamps in November 2422, November 2822, etc. in
52    America/Ciudad_Juarez.  (Problem reported by Gilmore Davidson.)
53
54    strftime %s now uses tm_gmtoff if available.  (Problem and draft
55    patch reported by Dag-Erling Smørgrav.)
56
57  Changes to build procedure
58
59    The leap-seconds.list file is now copied from the IERS instead of
60    from its downstream counterpart at NIST, as the IERS version is
61    now in the public domain too and tends to be more up-to-date.
62    (Thanks to Martin Burnicki for liaisoning with the IERS.)
63
64  Changes to documentation
65
66    The strftime man page documents which struct tm members affect
67    which conversion specs, and that tzset is called.  (Problems
68    reported by Robert Elz and Steve Summit.)
69
70
71Release 2023d - 2023-12-21 20:02:24 -0800
72
73  Briefly:
74    Ittoqqortoormiit, Greenland changes time zones on 2024-03-31.
75    Vostok, Antarctica changed time zones on 2023-12-18.
76    Casey, Antarctica changed time zones five times since 2020.
77    Code and data fixes for Palestine timestamps starting in 2072.
78    A new data file zonenow.tab for timestamps starting now.
79
80  Changes to future timestamps
81
82    Ittoqqortoormiit, Greenland (America/Scoresbysund) joins most of
83    the rest of Greenland's timekeeping practice on 2024-03-31, by
84    changing its time zone from -01/+00 to -02/-01 at the same moment
85    as the spring-forward transition.  Its clocks will therefore not
86    spring forward as previously scheduled.  The time zone change
87    reverts to its common practice before 1981.
88
89    Fix predictions for DST transitions in Palestine in 2072-2075,
90    correcting a typo introduced in 2023a.
91
92  Changes to past and future timestamps
93
94    Vostok, Antarctica changed to +05 on 2023-12-18.  It had been at
95    +07 (not +06) for years.  (Thanks to Zakhary V. Akulov.)
96
97    Change data for Casey, Antarctica to agree with timeanddate.com,
98    by adding five time zone changes since 2020.  Casey is now at +08
99    instead of +11.
100
101  Changes to past tm_isdst flags
102
103    Much of Greenland, represented by America/Nuuk, changed its
104    standard time from -03 to -02 on 2023-03-25, not on 2023-10-28.
105    This does not affect UTC offsets, only the tm_isdst flag.
106    (Thanks to Thomas M. Steenholdt.)
107
108  New data file
109
110    A new data file zonenow.tab helps configure applications that use
111    timestamps dated from now on.  This simplifies configuration,
112    since users choose from a smaller Zone set.  The file's format is
113    experimental and subject to change.
114
115  Changes to code
116
117    localtime.c no longer mishandles TZif files that contain a single
118    transition into a DST regime.  Previously, it incorrectly assumed
119    DST was in effect before the transition too.  (Thanks to Alois
120    Treindl for debugging help.)
121
122    localtime.c's timeoff no longer collides with OpenBSD 7.4.
123
124    The C code now uses _Generic only if __STDC_VERSION__ says the
125    compiler is C11 or later.
126
127    tzselect now optionally reads zonenow.tab, to simplify when
128    configuring only for timestamps dated from now on.
129
130    tzselect no longer creates temporary files.
131
132    tzselect no longer mishandles the following:
133
134      Spaces and most other special characters in BUGEMAIL, PACKAGE,
135      TZDIR, and VERSION.
136
137      TZ strings when using mawk 1.4.3, which mishandles regular
138      expressions of the form /X{2,}/.
139
140      ISO 6709 coordinates when using an awk that lacks the GNU
141      extension of newlines in -v option-arguments.
142
143      Non UTF-8 locales when using an iconv command that lacks the GNU
144      //TRANSLIT extension.
145
146    zic no longer mishandles data for Palestine after the year 2075.
147    Previously, it incorrectly omitted post-2075 transitions that are
148    predicted for just before and just after Ramadan.  (Thanks to Ken
149    Murchison for debugging help.)
150
151    zic now works again on Linux 2.6.16 and 2.6.17 (2006).
152    (Problem reported by Rune Torgersen.)
153
154  Changes to build procedure
155
156    The Makefile is now more compatible with POSIX:
157     * It no longer defines AR, CC, CFLAGS, LDFLAGS, and SHELL.
158     * It no longer uses its own 'cc' in place of CC.
159     * It now uses ARFLAGS, with default specified by POSIX.
160     * It does not use LFLAGS incompatibly with POSIX.
161     * It uses the special .POSIX target.
162     * It quotes special characters more carefully.
163     * It no longer mishandles builds in an ISO 8859 locale.
164    Due to the CC changes, TZDIR is now #defined in a file tzfile.h
165    built by 'make', not in a $(CC) -D option.  Also, TZDEFAULT is
166    now treated like TZDIR as they have similar roles.
167
168  Changes to commentary
169
170     Limitations and hazards of the optional support for obsolescent
171     C89 platforms are documented better, along with a tentative
172     schedule for removing this support.
173
174
175Release 2023c - 2023-03-28 12:42:14 -0700
176
177  Changes to past and future timestamps
178
179    Model Lebanon's DST chaos by reverting data to tzdb 2023a.
180    (Thanks to Rany Hany for the heads-up.)
181
182
183Release 2023b - 2023-03-23 19:50:38 -0700
184
185  Changes to future timestamps
186
187    This year Lebanon springs forward April 20/21 not March 25/26.
188    (Thanks to Saadallah Itani.)  [This was reverted in 2023c.]
189
190
191Release 2023a - 2023-03-22 12:39:33 -0700
192
193  Briefly:
194    Egypt now uses DST again, from April through October.
195    This year Morocco springs forward April 23, not April 30.
196    Palestine delays the start of DST this year.
197    Much of Greenland still uses DST from 2024 on.
198    America/Yellowknife now links to America/Edmonton.
199    tzselect can now use current time to help infer timezone.
200    The code now defaults to C99 or later.
201    Fix use of C23 attributes.
202
203  Changes to future timestamps
204
205    Starting in 2023, Egypt will observe DST from April's last Friday
206    through October's last Thursday.  (Thanks to Ahmad ElDardiry.)
207    Assume the transition times are 00:00 and 24:00, respectively.
208
209    In 2023 Morocco's spring-forward transition after Ramadan
210    will occur April 23, not April 30.  (Thanks to Milamber.)
211    Adjust predictions for future years accordingly.  This affects
212    predictions for 2023, 2031, 2038, and later years.
213
214    This year Palestine will delay its spring forward from
215    March 25 to April 29 due to Ramadan.  (Thanks to Heba Hamad.)
216    Make guesses for future Ramadans too.
217
218    Much of Greenland, represented by America/Nuuk, will continue to
219    observe DST using European Union rules.  When combined with
220    Greenland's decision not to change the clocks in fall 2023,
221    America/Nuuk therefore changes from -03/-02 to -02/-01 effective
222    2023-10-29 at 01:00 UTC.  (Thanks to Thomas M. Steenholdt.)
223    This change from 2022g doesn't affect timestamps until 2024-03-30,
224    and doesn't affect tm_isdst until 2023-03-25.
225
226  Changes to past timestamps
227
228    America/Yellowknife has changed from a Zone to a backward
229    compatibility Link, as it no longer differs from America/Edmonton
230    since 1970.  (Thanks to Almaz Mingaleev.)  This affects some
231    pre-1948 timestamps.  The old data are now in 'backzone'.
232
233  Changes to past time zone abbreviations
234
235    When observing Moscow time, Europe/Kirov and Europe/Volgograd now
236    use the abbreviations MSK/MSD instead of numeric abbreviations,
237    for consistency with other timezones observing Moscow time.
238
239  Changes to code
240
241    You can now tell tzselect local time, to simplify later choices.
242    Select the 'time' option in its first prompt.
243
244    You can now compile with -DTZNAME_MAXIMUM=N to limit time zone
245    abbreviations to N bytes (default 255).  The reference runtime
246    library now rejects POSIX-style TZ strings that contain longer
247    abbreviations, treating them as UTC.  Previously the limit was
248    platform dependent and abbreviations were silently truncated to
249    16 bytes even when the limit was greater than 16.
250
251    The code by default is now designed for C99 or later.  To build on
252    a mostly-C89 platform, compile with -DPORT_TO_C89; this should
253    work on C89 platforms that also support C99 'long long' and
254    perhaps a few other extensions to C89.  To support C89 callers of
255    tzcode's library, compile with -DSUPPORT_C89; however, this could
256    trigger latent bugs in C99-or-later callers.  The two new macros
257    are transitional aids planned to be removed in a future version
258    (say, in 2029), when C99 or later will be required.
259
260    The code now builds again on pre-C99 platforms, if you compile
261    with -DPORT_TO_C89.  This fixes a bug introduced in 2022f.
262
263    On C23-compatible platforms tzcode no longer uses syntax like
264    'static [[noreturn]] void usage(void);'.  Instead, it uses
265    '[[noreturn]] static void usage(void);' as strict C23 requires.
266    (Problem reported by Houge Langley.)
267
268    The code's functions now constrain their arguments with the C
269    'restrict' keyword consistently with their documentation.
270    This may allow future optimizations.
271
272    zdump again builds standalone with ckdadd and without setenv,
273    fixing a bug introduced in 2022g.  (Problem reported by panic.)
274
275    leapseconds.awk can now process a leap seconds file that never
276    expires; this might be useful if leap seconds are discontinued.
277
278  Changes to commentary
279
280    tz-link.html has a new section "Coordinating with governments and
281    distributors".  (Thanks to Neil Fuller for some of the text.)
282
283    To improve tzselect diagnostics, zone1970.tab's comments column is
284    now limited to countries that have multiple timezones.
285
286    Note that leap seconds are planned to be discontinued by 2035.
287
288
289Release 2022g - 2022-11-29 08:58:31 -0800
290
291  Briefly:
292    The northern edge of Chihuahua changes to US timekeeping.
293    Much of Greenland stops changing clocks after March 2023.
294    Fix some pre-1996 timestamps in northern Canada.
295    C89 is now deprecated; please use C99 or later.
296    Portability fixes for AIX, libintl, MS-Windows, musl, z/OS
297    In C code, use more C23 features if available.
298    C23 timegm now supported by default
299    Fixes for unlikely integer overflows
300
301  Changes to future timestamps
302
303    In the Mexican state of Chihuahua, the border strip near the US
304    will change to agree with nearby US locations on 2022-11-30.
305    The strip's western part, represented by Ciudad Juárez, switches
306    from -06 all year to -07/-06 with US DST rules, like El Paso, TX.
307    The eastern part, represented by Ojinaga, will observe US DST next
308    year, like Presidio, TX.  (Thanks to Heitor David Pinto.)
309    A new Zone America/Ciudad_Juarez splits from America/Ojinaga.
310
311    Much of Greenland, represented by America/Nuuk, stops observing
312    winter time after March 2023, so its daylight saving time becomes
313    standard time.  (Thanks to Jonas Nyrup and Jürgen Appel.)
314
315  Changes to past timestamps
316
317    Changes for pre-1996 northern Canada (thanks to Chris Walton):
318
319      Merge America/Iqaluit and America/Pangnirtung into the former,
320      with a backward compatibility link for the latter name.
321      There is no good evidence the two locations differ since 1970.
322      This change affects pre-1996 America/Pangnirtung timestamps.
323
324      Cambridge Bay, Inuvik, Iqaluit, Rankin Inlet, Resolute and
325      Yellowknife did not observe DST in 1965, and did observe DST
326      from 1972 through 1979.
327
328      Whitehorse moved from -09 to -08 on 1966-02-27, not 1967-05-28.
329
330    Colombia's 1993 fallback was 02-06 24:00, not 04-04 00:00.
331    (Thanks to Alois Treindl.)
332
333    Singapore's 1981-12-31 change was at 16:00 UTC (23:30 local time),
334    not 24:00 local time.  (Thanks to Geoff Clare via Robert Elz.)
335
336  Changes to code
337
338    Although tzcode still works with C89, bugs found in recent routine
339    maintenance indicate that bitrot has set in and that in practice
340    C89 is no longer used to build tzcode.  As it is a maintenance
341    burden, support for C89 is planned to be removed soon.  Instead,
342    please use compilers compatible with C99, C11, C17, or C23.
343
344    timegm, which tzcode implemented in 1989, will finally be
345    standardized 34 years later as part of C23, so timegm is now
346    supported even if STD_INSPIRED is not defined.
347
348    Fix bug in zdump's tzalloc emulation on hosts that lack tm_zone.
349    (Problem reported by Đoàn Trần Công Danh.)
350
351    Fix bug in zic on hosts where malloc(0) yields NULL on success.
352    (Problem reported by Tim McBrayer for AIX 6.1.)
353
354    Fix zic configuration to avoid linkage failures on some platforms.
355    (Problems reported by Gilmore Davidson and Igor Ivanov.)
356
357    Work around MS-Windows nmake incompatibility with POSIX.
358    (Problem reported by Manuela Friedrich.)
359
360    Port mktime and strftime to debugging platforms where accessing
361    uninitialized data has undefined behavior (strftime problem
362    reported by Robert Elz).
363
364    Check more carefully for unlikely integer overflows, preferring
365    C23 <stdckdint.h> to overflow checking by hand, as the latter has
366    had obscure bugs.
367
368  Changes to build procedure
369
370    New Makefile rule check_mild that skips checking whether Link
371    lines are in the file 'backward'.  (Inspired by a suggestion from
372    Stephen Colebourne.)
373
374
375Release 2022f - 2022-10-28 18:04:57 -0700
376
377  Briefly:
378    Mexico will no longer observe DST except near the US border.
379    Chihuahua moves to year-round -06 on 2022-10-30.
380    Fiji no longer observes DST.
381    Move links to 'backward'.
382    In vanguard form, GMT is now a Zone and Etc/GMT a link.
383    zic now supports links to links, and vanguard form uses this.
384    Simplify four Ontario zones.
385    Fix a Y2438 bug when reading TZif data.
386    Enable 64-bit time_t on 32-bit glibc platforms.
387    Omit large-file support when no longer needed.
388    In C code, use some C23 features if available.
389    Remove no-longer-needed workaround for Qt bug 53071.
390
391  Changes to future timestamps
392
393    Mexico will no longer observe DST after 2022, except for areas
394    near the US border that continue to observe US DST rules.
395    On 2022-10-30 at 02:00 the Mexican state of Chihuahua moves
396    from -07 (-06 with DST) to year-round -06, thus not changing
397    its clocks that day.  The new law states that Chihuahua
398    near the US border no longer observes US DST.
399    (Thanks to gera for the heads-up about Chihuahua.)
400
401    Fiji will not observe DST in 2022/3.  (Thanks to Shalvin Narayan.)
402    For now, assume DST is suspended indefinitely.
403
404  Changes to data
405
406    Move links to 'backward' to ease and simplify link maintenance.
407    This affects generated data only if you use 'make BACKWARD='.
408
409    GMT is now a Zone and Etc/GMT a link instead of vice versa,
410    as GMT is needed for leap second support whereas Etc/GMT is not.
411    However, this change exposes a bug in TZUpdater 2.3.2 so it is
412    present only in vanguard form for now.
413
414    Vanguard form now uses links to links, as zic now supports this.
415
416  Changes to past timestamps
417
418    Simplify four Ontario zones, as most of the post-1970 differences
419    seem to have been imaginary.  (Problem reported by Chris Walton.)
420    Move America/Nipigon, America/Rainy_River, and America/Thunder_Bay
421    to 'backzone'; backward-compatibility links still work, albeit
422    with some different timestamps before November 2005.
423
424  Changes to code
425
426    zic now supports links to links regardless of input line order.
427    For example, if Australia/Sydney is a Zone, the lines
428      Link Australia/Canberra Australia/ACT
429      Link Australia/Sydney Australia/Canberra
430    now work correctly, even though the shell commands
431      ln Australia/Canberra Australia/ACT
432      ln Australia/Sydney Australia/Canberra
433    would fail because the first command attempts to use a link
434    Australia/Canberra that does not exist until after the second
435    command is executed.  Previously, zic had unspecified behavior if
436    a Link line's target was another link, and zic often misbehaved if
437    a Link line's target was a later Link line.
438
439    Fix line number in zic's diagnostic for a link to a link.
440
441    Fix a bug that caused localtime to mishandle timestamps starting
442    in the year 2438 when reading data generated by 'zic -b fat' when
443    distant-future DST transitions occur at times given in standard
444    time or in UT, not the usual case of local time.  This occurs when
445    the corresponding .zi Rule lines specify DST transitions with TO
446    columns of 'max' and AT columns that end in 's' or 'u'.  The
447    number 2438 comes from the 32-bit limit in the year 2038, plus the
448    400-year Gregorian cycle.  (Problem reported by Bradley White.)
449
450    On glibc 2.34 and later, which optionally supports 64-bit time_t
451    on platforms like x86 where time_t was traditionally 32 bits,
452    default time_t to 64 instead of 32 bits.  This lets functions like
453    localtime support timestamps after the year 2038, and fixes
454    year-2038 problems in zic when accessing files dated after 2038.
455    To continue to limit time_t to 32 bits on these platforms, use
456    "make CFLAGS='-D_TIME_BITS=32'".
457
458    In C code, do not enable large-file support on platforms like AIX
459    and macOS that no longer need it now that tzcode does not use
460    off_t or related functions like 'stat'.  Large-file support is
461    still enabled by default on GNU/Linux, as it is needed for 64-bit
462    time_t support.
463
464    In C code, prefer C23 keywords to pre-C23 macros for alignof,
465    bool, false, and true.  Also, use the following C23 features if
466    available: __has_include, unreachable.
467
468    zic no longer works around Qt bug 53071, as the relevant Qt
469    releases have been out of support since 2019.  This change affects
470    only fat TZif files, as thin files never had the workaround.
471
472    zdump no longer modifies the environ vector when compiled on
473    platforms lacking tm_zone or when compiled with -DUSE_LTZ=0.
474    This avoid undefined behavior on POSIX platforms.
475
476
477Release 2022e - 2022-10-11 11:13:02 -0700
478
479  Briefly:
480    Jordan and Syria switch from +02/+03 with DST to year-round +03.
481
482  Changes to future timestamps
483
484    Jordan and Syria are abandoning the DST regime and are changing to
485    permanent +03, so they will not fall back from +03 to +02 on
486    2022-10-28.  (Thanks to Steffen Thorsen and Issam Al-Zuwairi.)
487
488  Changes to past timestamps
489
490    On 1922-01-01 Tijuana adopted standard time at 00:00, not 01:00.
491
492  Changes to past time zone abbreviations and DST flags
493
494    The temporary advancement of clocks in central Mexico in summer
495    1931 is now treated as daylight saving time, instead of as two
496    changes to standard time.
497
498
499Release 2022d - 2022-09-23 12:02:57 -0700
500
501  Briefly:
502    Palestine transitions are now Saturdays at 02:00.
503    Simplify three Ukraine zones into one.
504
505  Changes to future timestamps
506
507    Palestine now springs forward and falls back at 02:00 on the
508    first Saturday on or after March 24 and October 24, respectively.
509    This means 2022 falls back 10-29 at 02:00, not 10-28 at 01:00.
510    (Thanks to Heba Hamad.)
511
512  Changes to past timestamps
513
514    Simplify three Ukraine zones to one, since the post-1970
515    differences seem to have been imaginary.  Move Europe/Uzhgorod and
516    Europe/Zaporozhye to 'backzone'; backward-compatibility links
517    still work, albeit with different timestamps before October 1991.
518
519
520Release 2022c - 2022-08-15 17:47:18 -0700
521
522  Briefly:
523    Work around awk bug in FreeBSD, macOS, etc.
524    Improve tzselect on intercontinental Zones.
525
526  Changes to code
527
528    Work around a bug in onetrueawk that broke commands like
529    'make traditional_tarballs' on FreeBSD, macOS, etc.
530    (Problem reported by Deborah Goldsmith.)
531
532    Add code to tzselect that uses experimental structured comments in
533    zone1970.tab to clarify whether Zones like Africa/Abidjan and
534    Europe/Istanbul cross continent or ocean boundaries.
535    (Inspired by a problem reported by Peter Krefting.)
536
537    Fix bug with 'zic -d /a/b/c' when /a is unwritable but the
538    directory /a/b already exists.
539
540    Remove zoneinfo2tdf.pl, as it was unused and triggered false
541    malware alarms on some email servers.
542
543
544Release 2022b - 2022-08-10 15:38:32 -0700
545
546  Briefly:
547    Chile's DST is delayed by a week in September 2022.
548    Iran no longer observes DST after 2022.
549    Rename Europe/Kiev to Europe/Kyiv.
550    New zic -R option
551    Vanguard form now uses %z.
552    Finish moving duplicate-since-1970 zones to 'backzone'.
553    New build option PACKRATLIST
554    New tailored_tarballs target, replacing rearguard_tarballs
555
556  Changes to future timestamps
557
558    Chile's 2022 DST start is delayed from September 4 to September 11.
559    (Thanks to Juan Correa.)
560
561    Iran plans to stop observing DST permanently, after it falls back
562    on 2022-09-21.  (Thanks to Ali Mirjamali.)
563
564  Changes to past timestamps
565
566    Finish moving to 'backzone' the location-based zones whose
567    timestamps since 1970 are duplicates; adjust links accordingly.
568    This change ordinarily affects only pre-1970 timestamps, and with
569    the new PACKRATLIST option it does not affect any timestamps.
570    In this round the affected zones are Antarctica/Vostok,
571    Asia/Brunei, Asia/Kuala_Lumpur, Atlantic/Reykjavik,
572    Europe/Amsterdam, Europe/Copenhagen, Europe/Luxembourg,
573    Europe/Monaco, Europe/Oslo, Europe/Stockholm, Indian/Christmas,
574    Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Reunion,
575    Pacific/Chuuk, Pacific/Funafuti, Pacific/Majuro, Pacific/Pohnpei,
576    Pacific/Wake and Pacific/Wallis, and the affected links are
577    Arctic/Longyearbyen, Atlantic/Jan_Mayen, Iceland, Pacific/Ponape,
578    Pacific/Truk, and Pacific/Yap.
579
580    From fall 1994 through fall 1995, Shanks wrote that Crimea's
581    DST transitions were at 02:00 standard time, not at 00:00.
582    (Thanks to Michael Deckers.)
583
584    Iran adopted standard time in 1935, not 1946.  In 1977 it observed
585    DST from 03-21 23:00 to 10-20 24:00; its 1978 transitions were on
586    03-24 and 08-05, not 03-20 and 10-20; and its spring 1979
587    transition was on 05-27, not 03-21.
588    (Thanks to Roozbeh Pournader and Francis Santoni.)
589
590    Chile's observance of -04 from 1946-08-29 through 1947-03-31 was
591    considered DST, not standard time.  Santiago and environs had moved
592    their clocks back to rejoin the rest of mainland Chile; put this
593    change at the end of 1946-08-28.  (Thanks to Michael Deckers.)
594
595    Some old, small clock transitions have been removed, as people at
596    the time did not change their clocks.  This affects Asia/Hong_Kong
597    in 1904, Asia/Ho_Chi_Minh in 1906, and Europe/Dublin in 1880.
598
599  Changes to zone name
600
601    Rename Europe/Kiev to Europe/Kyiv, as "Kyiv" is more common in
602    English now.  Spelling of other names in Ukraine has not yet
603    demonstrably changed in common English practice so for now these
604    names retain old spellings, as in other countries (e.g.,
605    Europe/Prague not "Praha", and Europe/Sofia not "Sofiya").
606
607  Changes to code
608
609    zic has a new option '-R @N' to output explicit transitions < N.
610    (Need suggested by Almaz Mingaleev.)
611
612    'zic -r @N' no longer outputs bad data when N < first transition.
613    (Problem introduced in 2021d and reported by Peter Krefting.)
614
615    zic now checks its input for NUL bytes and unterminated lines, and
616    now supports input line lengths up to 2048 (not 512) bytes.
617
618    gmtime and related code now use the abbreviation "UTC" not "GMT".
619    POSIX is being revised to require this.
620
621    When tzset and related functions set vestigial static variables
622    like tzname, they now prefer specified timestamps to unspecified ones.
623    (Problem reported by Almaz Mingaleev.)
624
625    zic no longer complains "can't determine time zone abbreviation to
626    use just after until time" when a transition to a new standard
627    time occurs simultaneously with the first DST fallback transition.
628
629  Changes to build procedure
630
631    Source data in vanguard form now uses the %z notation, introduced
632    in release 2015f.  For example, for America/Sao_Paulo vanguard
633    form contains the zone continuation line "-3:00 Brazil %z", which
634    is simpler and more reliable than the line "-3:00 Brazil -03/-02"
635    used in main and rearguard forms.  The plan is for the main form
636    to use %z eventually; in the meantime maintainers of zi parsers
637    are encouraged to test the parsers on vanguard.zi.
638
639    The Makefile has a new PACKRATLIST option to select a subset of
640    'backzone'.  For example, 'make PACKRATDATA=backzone
641    PACKRATLIST=zone.tab' now generates TZif files identical to those
642    of the global-tz project.
643
644    The Makefile has a new tailored_tarballs target for generating
645    special-purpose tarballs.  It generalizes and replaces the
646    rearguard_tarballs target and related targets and macros, which
647    are now obsolescent.
648
649    'make install' now defaults LOCALTIME to Factory not GMT,
650    which means the default abbreviation is now "-00" not "GMT".
651
652    Remove the posix_packrat target, marked obsolescent in 2016a.
653
654
655Release 2022a - 2022-03-15 23:02:01 -0700
656
657  Briefly:
658    Palestine will spring forward on 2022-03-27, not -03-26.
659    zdump -v now outputs better failure indications.
660    Bug fixes for code that reads corrupted TZif data.
661
662  Changes to future timestamps
663
664    Palestine will spring forward on 2022-03-27, not 2022-03-26.
665    (Thanks to Heba Hamad.)  Predict future transitions for first
666    Sunday >= March 25.  Additionally, predict fallbacks to be the first
667    Friday on or after October 23, not October's last Friday, to be more
668    consistent with recent practice.  The first differing fallback
669    prediction is on 2025-10-24, not 2025-10-31.
670
671  Changes to past timestamps
672
673    From 1992 through spring 1996, Ukraine's DST transitions were at
674    02:00 standard time, not at 01:00 UTC.  (Thanks to Alois Treindl.)
675
676    Chile's Santiago Mean Time and its LMT precursor have been adjusted
677    eastward by 1 second to align with past and present law.
678
679  Changes to commentary
680
681    Add several references for Chile's 1946/1947 transitions, some of
682    which only affected portions of the country.
683
684  Changes to code
685
686    Fix bug when mktime gets confused by truncated TZif files with
687    unspecified local time.  (Problem reported by Almaz Mingaleev.)
688
689    Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
690    (Problem reported by Christos Zoulas.)
691
692    When reading a version 2 or later TZif file, the TZif reader now
693    validates the version 1 header and data block only enough to skip
694    over them, as recommended by RFC 8536 section 4.  Also, the TZif
695    reader no longer mistakenly attempts to parse a version 1 TZIf
696    file header as a TZ string.
697
698    zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
699    when local time and UT cannot be determined for a timestamp.
700
701  Changes to build procedure
702
703    Distribution tarballs now use standard POSIX.1-1988 ustar format
704    instead of GNU format.  Although the formats are almost identical
705    for these tarballs, ustar headers' magic fields contain "ustar"
706    instead of "ustar ", and their version fields contain "00" instead
707    of " ".  The two formats are planned to diverge more significantly
708    for tzdb releases after 2242-03-16 12:56:31 UTC, when the ustar
709    format becomes obsolete and the tarballs switch to pax format, an
710    extension of ustar.  For details about these formats, please see
711    "pax - portable archive interchange", IEEE Std 1003.1-2017,
712    <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13>.
713
714
715Release 2021e - 2021-10-21 18:41:00 -0700
716
717  Changes to future timestamps
718
719    Palestine will fall back 10-29 (not 10-30) at 01:00.
720    (Thanks to P Chan and Heba Hemad.)
721
722
723Release 2021d - 2021-10-15 13:48:18 -0700
724
725  Briefly:
726    Fiji suspends DST for the 2021/2022 season.
727    'zic -r' marks unspecified timestamps with "-00".
728
729  Changes to future timestamps
730
731    Fiji will suspend observance of DST for the 2021/2022 season.
732    Assume for now that it will return next year.  (Thanks to Jashneel
733    Kumar and P Chan.)
734
735  Changes to code
736
737    'zic -r' now uses "-00" time zone abbreviations for intervals
738    with UT offsets that are unspecified due to -r truncation.
739    This implements a change in draft Internet RFC 8536bis.
740
741
742Release 2021c - 2021-10-01 14:21:49 -0700
743
744  Briefly:
745    Revert most 2021b changes to 'backward'.
746    Fix 'zic -b fat' bug in pre-1970 32-bit data.
747    Fix two Link line typos.
748    Distribute SECURITY file.
749
750    This release is intended as a bugfix release, to fix compatibility
751    problems and typos reported since 2021b was released.
752
753  Changes to Link directives
754
755    Revert almost all of 2021b's changes to the 'backward' file,
756    by moving Link directives back to where they were in 2021a.
757    Although 'zic' doesn't care which source file contains a Link
758    directive, some downstream uses ran into trouble with the move.
759    (Problem reported by Stephen Colebourne for Joda-Time.)
760
761    Fix typo that linked Atlantic/Jan_Mayen to the wrong location
762    (problem reported by Chris Walton).
763
764    Fix 'backzone' typo that linked America/Virgin to the wrong
765    location (problem reported by Michael Deckers).
766
767  Changes to code
768
769    Fix a bug in 'zic -b fat' that caused old timestamps to be
770    mishandled in 32-bit-only readers (problem reported by Daniel
771    Fischer).
772
773  Changes to documentation
774
775    Distribute the SECURITY file (problem reported by Andreas Radke).
776
777
778Release 2021b - 2021-09-24 16:23:00 -0700
779
780  Briefly:
781    Jordan now starts DST on February's last Thursday.
782    Samoa no longer observes DST.
783    Merge more location-based Zones whose timestamps agree since 1970.
784    Move some backward-compatibility links to 'backward'.
785    Rename Pacific/Enderbury to Pacific/Kanton.
786    Correct many pre-1993 transitions in Malawi, Portugal, etc.
787    zic now creates each output file or link atomically.
788    zic -L no longer omits the POSIX TZ string in its output.
789    zic fixes for truncation and leap second table expiration.
790    zic now follows POSIX for TZ strings using all-year DST.
791    Fix some localtime crashes and bugs in obscure cases.
792    zdump -v now outputs more-useful boundary cases.
793    tzfile.5 better matches a draft successor to RFC 8536.
794    A new file SECURITY.
795
796    This release is prompted by recent announcements by Jordan and Samoa.
797    It incorporates many other changes that had accumulated since 2021a.
798    However, it omits most proposed changes that merged all Zones
799    agreeing since 1970, as concerns were raised about doing too many of
800    these changes at once.  It does keeps some of these changes in the
801    interest of making tzdb more equitable one step at a time; see
802    "Merge more location-based Zones" below.
803
804  Changes to future timestamps
805
806    Jordan now starts DST on February's last Thursday.
807    (Thanks to Steffen Thorsen.)
808
809    Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
810
811  Changes to zone name
812
813    Rename Pacific/Enderbury to Pacific/Kanton.  When we added
814    Enderbury in 1993, we did not know that it is uninhabited and that
815    Kanton (population two dozen) is the only inhabited location in
816    that timezone.  The old name is now a backward-compatibility link.
817
818  Changes to past timestamps
819
820    Correct many pre-1993 transitions, fixing entries originally
821    derived from Shanks, Whitman, and Mundell.  The fixes include:
822      - Barbados: standard time was introduced in 1911, not 1932; and
823	DST was observed in 1942-1944
824      - Cook Islands: In 1899 they switched from east to west of GMT,
825	celebrating Christmas for two days.  They (and Niue) switched
826	to standard time in 1952, not 1901.
827      - Guyana: corrected LMT for Georgetown; the introduction of
828	standard time in 1911, not 1915; and corrections to 1975 and
829	1992 transitions
830      - Kanton: uninhabited before 1937-08-31
831      - Niue: only observed -11:20 from 1952 through 1964, then went to
832        -11 instead of -11:30
833      - Portugal: DST was observed in 1950
834      - Tonga: corrected LMT; the introduction of standard time in 1945,
835        not 1901; and corrections to the transition from +12:20 to +13
836        in 1961, not 1941
837    Additional fixes to entries in the 'backzone' file include:
838      - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
839      - The Gambia: 1933 and 1942 transitions
840      - Malawi: several 1911 through 1925 transitions
841      - Sierra Leone: several 1913 through 1941 transitions, and DST
842	was NOT observed in 1957 through 1962
843    (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
844    Alois Treindl.)
845
846    Merge more location-based Zones whose timestamps agree since 1970,
847    as pre-1970 timestamps are out of scope.  This is part of a
848    process that has been ongoing since 2013.  This does not affect
849    post-1970 timestamps, and timezone historians who build with 'make
850    PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
851    When merging, keep the most-populous location's data, and move
852    data for other locations to 'backzone' with a backward
853    link in 'backward'.  For example, move America/Creston data to
854    'backzone' with a link in 'backward' from America/Phoenix because
855    the two timezones' timestamps agree since 1970; this change
856    affects some pre-1968 timestamps in America/Creston because
857    Creston and Phoenix disagreed before 1968.  The affected Zones
858    are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
859    America/Creston, America/Curacao, America/Nassau,
860    America/Port_of_Spain, Antarctica/DumontDUrville, and
861    Antarctica/Syowa.
862
863  Changes to maintenance procedure
864
865    The new file SECURITY covers how to report security-related bugs.
866
867    Several backward-compatibility links have been moved to the
868    'backward' file.  These links, which range from Africa/Addis_Ababa
869    to Pacific/Saipan, are only for compatibility with now-obsolete
870    guidelines suggesting an entry for every ISO 3166 code.
871    The intercontinental convenience links Asia/Istanbul and
872    Europe/Nicosia have also been moved to 'backward'.
873
874  Changes to code
875
876    zic now creates each output file or link atomically,
877    possibly by creating a temporary file and then renaming it.
878    This avoids races where a TZ setting would temporarily stop
879    working while zic was installing a replacement file or link.
880
881    zic -L no longer omits the POSIX TZ string in its output.
882    Starting with 2020a, zic -L truncated its output according to the
883    "Expires" directive or "#expires" comment in the leapseconds file.
884    The resulting TZif files omitted daylight saving transitions after
885    the leap second table expired, which led to far less accurate
886    predictions of times after the expiry.  Although future timestamps
887    cannot be converted accurately in the presence of leap seconds, it
888    is more accurate to convert near-future timestamps with a few
889    seconds error than with an hour error, so zic -L no longer
890    truncates output in this way.
891
892    Instead, when zic -L is given the "Expires" directive, it now
893    outputs the expiration by appending a no-change entry to the leap
894    second table.  Although this should work well with most TZif
895    readers, it does not conform to Internet RFC 8536 and some pickier
896    clients (including tzdb 2017c through 2021a) reject it, so
897    "Expires" directives are currently disabled by default.  To enable
898    them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
899    this new feature it is marked with a new TZif version number 4,
900    a format intended to be documented in a successor to RFC 8536.
901    The old-format "#expires" comments are now treated solely as
902    comments and have no effect on the TZif files.
903
904    zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
905    that omits leap second information for the range LO..B when LO
906    falls between two leap seconds A and B.  Instead, it generates a
907    TZif version 4 file that represents the previously missing
908    information.
909
910    The TZif reader now allows the leap second table to begin with a
911    correction other than -1 or +1, and to contain adjacent
912    transitions with equal corrections.  This supports TZif version 4.
913
914    The TZif reader now lets leap seconds occur less than 28 days
915    apart.  This supports possible future TZif extensions.
916
917    Fix bug that caused 'localtime' etc. to crash when TZ was
918    set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
919    not conform to POSIX but does conform to Internet RFC 8536.
920
921    Fix another bug that caused 'localtime' etc. to crash when TZ was
922    set to a POSIX-conforming but unusual TZ string like
923    "EST5EDT4,0/0,J365/0", where almost all the year is DST.
924
925    Fix yet another bug that caused 'localtime' etc. to mishandle slim
926    TZif files containing leap seconds after the last explicit
927    transition in the table, or when handling far-future timestamps
928    in slim TZif files lacking leap seconds.
929
930    Fix localtime misbehavior involving positive leap seconds.
931    This change affects only behavior for "right" system time,
932    which contains leap seconds, and only if the UT offset is
933    not a multiple of 60 seconds when a positive leap second occurs.
934    (No such timezone exists in tzdb, luckily.)  Without the fix,
935    the timestamp was ambiguous during a positive leap second.
936    With the fix, any seconds occurring after a positive leap second
937    and within the same localtime minute are counted through 60, not
938    through 59; their UT offset (tm_gmtoff) is the same as before.
939    Here is how the fix affects timestamps in a timezone with UT
940    offset +01:23:45 (5025 seconds) and with a positive leap second at
941    1972-06-30 23:59:60 UTC (78796800):
942
943	time_t    without the fix      with the fix
944	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
945	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
946	...
947	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
948	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
949
950    Fix an unlikely bug that caused 'localtime' etc. to misbehave if
951    civil time changes a few seconds before time_t wraps around, when
952    leap seconds are enabled.
953
954    Fix bug in zic -r; in some cases, the dummy time type after the
955    last time transition disagreed with the TZ string, contrary to
956    Internet RFC 8563 section 3.3.
957
958    Fix a bug with 'zic -r @X' when X is a negative leap second that
959    has a nonnegative correction.  Without the fix, the output file
960    was truncated so that X appeared to be a positive leap second.
961    Fix a similar, even less likely bug when truncating at a positive
962    leap second that has a nonpositive correction.
963
964    zic -r now reports an error if given rolling leap seconds, as this
965    usage has never generally worked and is evidently unused.
966
967    zic now generates a POSIX-conforming TZ string for TZif files
968    where all-year DST is predicted for the indefinite future.
969    For example, for all-year Eastern Daylight Time, zic now generates
970    "XXX3EDT4,0/0,J365/23" where it previously generated
971    "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
972    noting the possibility of POSIX conformance.)
973
974    zic.c no longer requires sys/wait.h (thanks to spazmodius for
975    noting it wasn't needed).
976
977    When reading slim TZif files, zdump no longer mishandles leap
978    seconds on the rare platforms where time_t counts leap seconds,
979    fixing a bug introduced in 2014g.
980
981    zdump -v now outputs timestamps at boundaries of what localtime
982    and gmtime can represent, instead of the less useful timestamps
983    one day after the minimum and one day before the maximum.
984    (Thanks to Arthur David Olson for prototype code, and to Manuela
985    Friedrich for debugging help.)
986
987    zdump's -c and -t options are now consistently inclusive for the
988    lower time bound and exclusive for the upper.  Formerly they were
989    inconsistent.  (Confusion noted by Martin Burnicki.)
990
991  Changes to build procedure
992
993    You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
994    non-POSIX hosts where malloc doesn't set errno.
995    (Problem reported by Jan Engelhardt.)
996
997  Changes to documentation
998
999    tzfile.5 better matches a draft successor to RFC 8536
1000    <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.
1001
1002
1003Release 2021a - 2021-01-24 10:54:57 -0800
1004
1005  Changes to future timestamps
1006
1007    South Sudan changes from +03 to +02 on 2021-02-01 at 00:00.
1008    (Thanks to Steffen Thorsen.)
1009
1010
1011Release 2020f - 2020-12-29 00:17:46 -0800
1012
1013  Change to build procedure
1014
1015    'make rearguard_tarballs' no longer generates a bad rearguard.zi,
1016    fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
1017
1018
1019Release 2020e - 2020-12-22 15:14:34 -0800
1020
1021  Briefly:
1022    Volgograd switches to Moscow time on 2020-12-27 at 02:00.
1023
1024  Changes to future timestamps
1025
1026    Volgograd changes time zone from +04 to +03 on 2020-12-27 at 02:00.
1027    (Thanks to Alexander Krivenyshev and Stepan Golosunov.)
1028
1029  Changes to past timestamps
1030
1031    Correct many pre-1986 transitions, fixing entries originally
1032    derived from Shanks.  The fixes include:
1033      - Australia: several 1917 through 1971 transitions
1034      - The Bahamas: several 1941 through 1945 transitions
1035      - Bermuda: several 1917 through 1956 transitions
1036      - Belize: several 1942 through 1968 transitions
1037      - Ghana: several 1915 through 1956 transitions
1038      - Israel and Palestine: several 1940 through 1985 transitions
1039      - Kenya and adjacent: several 1908 through 1960 transitions
1040      - Nigeria and adjacent: correcting LMT in Lagos, and several 1905
1041        through 1919 transitions
1042      - Seychelles: the introduction of standard time in 1907, not 1906
1043      - Vanuatu: DST in 1973-1974, and a corrected 1984 transition
1044    (Thanks to P Chan.)
1045
1046    Because of the Australia change, Australia/Currie (King Island) is
1047    no longer needed, as it is identical to Australia/Hobart for all
1048    timestamps since 1970 and was therefore created by mistake.
1049    Australia/Currie has been moved to the 'backward' file and its
1050    corrected data moved to the 'backzone' file.
1051
1052  Changes to past time zone abbreviations and DST flags
1053
1054    To better match legislation in Turks and Caicos, the 2015 shift to
1055    year-round observance of -04 is now modeled as AST throughout before
1056    returning to Eastern Time with US DST in 2018, rather than as
1057    maintaining EDT until 2015-11-01.  (Thanks to P Chan.)
1058
1059  Changes to documentation
1060
1061    The zic man page now documents zic's coalescing of transitions
1062    when a zone falls back just before DST springs forward.
1063
1064
1065Release 2020d - 2020-10-21 11:24:13 -0700
1066
1067  Briefly:
1068    Palestine ends DST earlier than predicted, on 2020-10-24.
1069
1070  Changes to past and future timestamps
1071
1072    Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
1073    as previously predicted (thanks to Sharef Mustafa.)  Its
1074    2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
1075    Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
1076    its spring 2020 transition was on March 28 at 00:00, not March 27
1077    (thanks to Pierre Cashon.)  This affects Asia/Gaza and
1078    Asia/Hebron.  Assume future spring and fall transitions will be on
1079    the Saturday preceding the last Sunday of March and October,
1080    respectively.
1081
1082
1083Release 2020c - 2020-10-16 11:15:53 -0700
1084
1085  Briefly:
1086    Fiji starts DST later than usual, on 2020-12-20.
1087
1088  Changes to future timestamps
1089
1090    Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
1091    previously predicted.  DST will still end on 2021-01-17.
1092    (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
1093    the later-than-usual start date is a one-time departure from the
1094    recent pattern.
1095
1096  Changes to build procedure
1097
1098    Rearguard tarballs now contain an empty file pacificnew.
1099    Some older downstream software expects this file to exist.
1100    (Problem reported by Mike Cullinan.)
1101
1102
1103Release 2020b - 2020-10-06 18:35:04 -0700
1104
1105  Briefly:
1106    Revised predictions for Morocco's changes starting in 2023.
1107    Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
1108    Macquarie Island has stayed in sync with Tasmania since 2011.
1109    Casey, Antarctica is at +08 in winter and +11 in summer.
1110    zic no longer supports -y, nor the TYPE field of Rules.
1111
1112  Changes to future timestamps
1113
1114    Morocco's spring-forward after Ramadan is now predicted to occur
1115    no sooner than two days after Ramadan, instead of one day.
1116    (Thanks to Milamber.)  The first altered prediction is for 2023,
1117    now predicted to spring-forward on April 30 instead of April 23.
1118
1119  Changes to past and future timestamps
1120
1121   Casey Station, Antarctica has been using +08 in winter and +11 in
1122   summer since 2018.  The most recent transition from +08 to +11 was
1123   2020-10-04 00:01.  Also, Macquarie Island has been staying in
1124   sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
1125
1126  Changes to past and future time zone abbreviations and DST flags
1127
1128    Canada's Yukon, represented by America/Whitehorse and
1129    America/Dawson, changes its time zone rules from -08/-07 to
1130    permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
1131    This change affects only the time zone abbreviation (MST vs PDT)
1132    and daylight saving flag for the period between the two dates.
1133    (Thanks to Andrew G. Smith.)
1134
1135  Changes to past timestamps
1136
1137    Correct several transitions for Hungary for 1918/1983.
1138    For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
1139    (Thanks to Géza Nyáry.)  Also, the 1890 transition to standard
1140    time was on 11-01, not 10-01 (thanks to Michael Deckers).
1141
1142    The 1891 French transition was on March 16, not March 15.  The
1143    1911-03-11 French transition was at midnight, not a minute later.
1144    Monaco's transitions were on 1892-06-01 and 1911-03-29, not
1145    1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
1146
1147  Changes to code
1148
1149    Support for zic's long-obsolete '-y YEARISTYPE' option has been
1150    removed and, with it, so has support for the TYPE field in Rule
1151    lines, which is now reserved for compatibility with earlier zic.
1152    These features were previously deprecated in release 2015f.
1153    (Thanks to Tim Parenti.)
1154
1155    zic now defaults to '-b slim' instead of to '-b fat'.
1156
1157    zic's new '-l -' and '-p -' options uninstall any existing
1158    localtime and posixrules files, respectively.
1159
1160    The undocumented and ineffective tzsetwall function has been
1161    removed.
1162
1163  Changes to build procedure
1164
1165    The Makefile now defaults POSIXRULES to '-', so the posixrules
1166    feature (obsolete as of 2019b) is no longer installed by default.
1167
1168  Changes to documentation and commentary
1169
1170    The long-obsolete files pacificnew, systemv, and yearistype.sh have
1171    been removed from the distribution.  (Thanks to Tim Parenti.)
1172
1173
1174Release 2020a - 2020-04-23 16:03:47 -0700
1175
1176  Briefly:
1177    Morocco springs forward on 2020-05-31, not 2020-05-24.
1178    Canada's Yukon advanced to -07 year-round on 2020-03-08.
1179    America/Nuuk renamed from America/Godthab.
1180    zic now supports expiration dates for leap second lists.
1181
1182  Changes to future timestamps
1183
1184    Morocco's second spring-forward transition in 2020 will be May 31,
1185    not May 24 as predicted earlier.  (Thanks to Semlali Naoufal.)
1186    Adjust future-year predictions to use the first Sunday after the
1187    day after Ramadan, not the first Sunday after Ramadan.
1188
1189    Canada's Yukon, represented by America/Whitehorse and
1190    America/Dawson, advanced to -07 year-round, beginning with its
1191    spring-forward transition on 2020-03-08, and will not fall back on
1192    2020-11-01.  Although a government press release calls this
1193    "permanent Pacific Daylight Saving Time", we prefer MST for
1194    consistency with nearby Dawson Creek, Creston, and Fort Nelson.
1195    (Thanks to Tim Parenti.)
1196
1197  Changes to past timestamps
1198
1199    Shanghai observed DST in 1919.  (Thanks to Phake Nick.)
1200
1201  Changes to timezone identifiers
1202
1203    To reflect current usage in English better, America/Godthab has
1204    been renamed to America/Nuuk.  A backwards-compatibility link
1205    remains for the old name.
1206
1207  Changes to code
1208
1209    localtime.c no longer mishandles timestamps after the last
1210    transition in a TZif file with leap seconds and with daylight
1211    saving time transitions projected into the indefinite future.
1212    For example, with TZ='America/Los_Angeles' with leap seconds,
1213    zdump formerly reported a DST transition on 2038-03-14
1214    from 01:59:32.999... to 02:59:33 instead of the correct transition
1215    from 01:59:59.999... to 03:00:00.
1216
1217    zic -L now supports an Expires line in the leapseconds file, and
1218    truncates the TZif output accordingly.  This propagates leap
1219    second expiration information into the TZif file, and avoids the
1220    abovementioned localtime.c bug as well as similar bugs present in
1221    many client implementations.  If no Expires line is present, zic
1222    -L instead truncates the TZif output based on the #expires comment
1223    present in leapseconds files distributed by tzdb 2018f and later;
1224    however, this usage is obsolescent.  For now, the distributed
1225    leapseconds file has an Expires line that is commented out, so
1226    that the file can be fed to older versions of zic which ignore the
1227    commented-out line.  Future tzdb distributions are planned to
1228    contain a leapseconds file with an Expires line.
1229
1230    The configuration macros HAVE_TZNAME and USG_COMPAT should now be
1231    set to 1 if the system library supports the feature, and 2 if not.
1232    As before, these macros are nonzero if tzcode should support the
1233    feature, zero otherwise.
1234
1235    The configuration macro ALTZONE now has the same values with the
1236    same meaning as HAVE_TZNAME and USG_COMPAT.
1237
1238    The code's defense against CRLF in leap-seconds.list is now
1239    portable to POSIX awk.  (Problem reported by Deborah Goldsmith.)
1240
1241    Although the undocumented tzsetwall function is not changed in
1242    this release, it is now deprecated in preparation for removal in
1243    future releases.  Due to POSIX requirements, tzsetwall has not
1244    worked for some time.  Any code that uses it should instead use
1245    tzalloc(NULL) or, if portability trumps thread-safety, should
1246    unset the TZ environment variable.
1247
1248  Changes to commentary
1249
1250    The Îles-de-la-Madeleine and the Listuguj reserve are noted as
1251    following America/Halifax, and comments about Yukon's "south" and
1252    "north" have been corrected to say "east" and "west".  (Thanks to
1253    Jeffery Nichols.)
1254
1255
1256Release 2019c - 2019-09-11 08:59:48 -0700
1257
1258  Briefly:
1259    Fiji observes DST from 2019-11-10 to 2020-01-12.
1260    Norfolk Island starts observing Australian-style DST.
1261
1262  Changes to future timestamps
1263
1264    Fiji's next DST transitions will be 2019-11-10 and 2020-01-12
1265    instead of 2019-11-03 and 2020-01-19.  (Thanks to Raymond Kumar.)
1266    Adjust future guesses accordingly.
1267
1268    Norfolk Island will observe Australian-style DST starting in
1269    spring 2019.  The first transition is on 2019-10-06.  (Thanks to
1270    Kyle Czech and Michael Deckers.)
1271
1272  Changes to past timestamps
1273
1274    Many corrections to time in Turkey from 1940 through 1985.
1275    (Thanks to Oya Vulaş via Alois Treindl, and to Kıvanç Yazan.)
1276
1277    The Norfolk Island 1975-03-02 transition was at 02:00 standard
1278    time, not 02:00 DST.  (Thanks to Michael Deckers.)
1279
1280    South Korea observed DST from 1948 through 1951.  Although this
1281    info was supposed to appear in release 2014j, a typo inadvertently
1282    suppressed the change.  (Thanks to Alois Treindl.)
1283
1284    Detroit observed DST in 1967 and 1968 following the US DST rules,
1285    except that its 1967 DST began on June 14 at 00:01.  (Thanks to
1286    Alois Treindl for pointing out that the old data entries were
1287    probably wrong.)
1288
1289    Fix several errors in pre-1970 transitions in Perry County, IN.
1290    (Thanks to Alois Treindl for pointing out the 1967/9 errors.)
1291
1292    Edmonton did not observe DST in 1967 or 1969.  In 1946 Vancouver
1293    ended DST on 09-29 not 10-13, and Vienna ended DST on 10-07 not
1294    10-06.  In 1945 Königsberg (now Kaliningrad) switched from +01/+02
1295    to +02/+03 on 04-10 not 01-01, and its +02/+03 is abbreviated
1296    EET/EEST, not CET/CEST.  (Thanks to Alois Treindl.)  In 1946
1297    Königsberg switched to +03 on 04-07 not 01-01.
1298
1299    In 1946 Louisville switched from CST to CDT on 04-28 at 00:01, not
1300    01-01 at 00:00.  (Thanks to Alois Treindl and Michael Deckers.)
1301    Also, it switched from CST to CDT on 1950-04-30, not 1947-04-27.
1302
1303    The 1892-05-01 transition in Brussels was at 00:17:30, not at noon.
1304    (Thanks to Michael Deckers.)
1305
1306  Changes to past time zone abbreviations and DST flags
1307
1308    Hong Kong Winter Time, observed from 1941-10-01 to 1941-12-25,
1309    is now flagged as DST and is abbreviated HKWT not HKT.
1310
1311  Changes to code
1312
1313    leapseconds.awk now relies only on its input data, rather than
1314    also relying on its comments.  (Inspired by code from Dennis
1315    Ferguson and Chris Woodbury.)
1316
1317    The code now defends against CRLFs in leap-seconds.list.
1318    (Thanks to Brian Inglis and Chris Woodbury.)
1319
1320  Changes to documentation and commentary
1321
1322    theory.html discusses leap seconds.  (Thanks to Steve Summit.)
1323
1324    Nashville's newspapers dueled about the time of day in the 1950s.
1325    (Thanks to John Seigenthaler.)
1326
1327    Liechtenstein observed Swiss DST in 1941/2.
1328    (Thanks to Alois Treindl.)
1329
1330
1331Release 2019b - 2019-07-01 00:09:53 -0700
1332
1333  Briefly:
1334    Brazil no longer observes DST.
1335    'zic -b slim' outputs smaller TZif files; please try it out.
1336    Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
1337
1338  Changes to future timestamps
1339
1340    Brazil has canceled DST and will stay on standard time indefinitely.
1341    (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
1342    Oliveira.)
1343
1344    Predictions for Morocco now go through 2087 instead of 2037, to
1345    work around a problem on newlib when using TZif files output by
1346    zic 2019a or earlier.  (Problem reported by David Gauchard.)
1347
1348  Changes to past and future timestamps
1349
1350    Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
1351    at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
1352    future transitions to be March's last Friday at 00:00.
1353
1354  Changes to past timestamps
1355
1356    Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
1357    03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
1358    not 09-15 at 00:00.  In 1946 its spring-forward transition was on
1359    04-21 at 00:00, not the previous day at 03:30.  From 1946 through
1360    1952 its fall-back transitions occurred at 04:30, not at 03:30.
1361    In 1947 its fall-back transition was on 11-30, not 12-30.
1362    (Thanks to P Chan.)
1363
1364  Changes to past time zone abbreviations
1365
1366    Italy's 1866 transition to Rome Mean Time was on December 12, not
1367    September 22.  This affects only the time zone abbreviation for
1368    Europe/Rome between those dates.  (Thanks to Stephen Trainor and
1369    Luigi Rosa.)
1370
1371  Changes affecting metadata only
1372
1373    Add info about the Crimea situation in zone1970.tab and zone.tab.
1374    (Problem reported by Serhii Demediuk.)
1375
1376  Changes to code
1377
1378    zic's new -b option supports a way to control data bloat and to
1379    test for year-2038 bugs in software that reads TZif files.
1380    'zic -b fat' and 'zic -b slim' generate larger and smaller output;
1381    for example, changing from fat to slim shrinks the Europe/London
1382    file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
1383    files represent the same set of timestamps and use the same TZif
1384    format as documented in tzfile(5) and in Internet RFC 8536.
1385    Fat format attempts to work around bugs or incompatibilities in
1386    older software, notably software that mishandles 64-bit TZif data
1387    or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
1388    Slim format is more efficient and does not work around 64-bit bugs
1389    or obsolete TZ strings.  Currently zic defaults to fat format
1390    unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
1391    out-of-the-box default is intended to change in future releases
1392    as the buggy software often mishandles timestamps anyway.
1393
1394    zic no longer treats a set of rules ending in 2037 specially.
1395    Previously, zic assumed that such a ruleset meant that future
1396    timestamps could not be predicted, and therefore omitted a
1397    POSIX-like TZ string in the TZif output.  The old behavior is no
1398    longer needed for current tzdata, and caused problems with newlib
1399    when used with older tzdata (reported by David Gauchard).
1400
1401    zic no longer generates some artifact transitions.  For example,
1402    Europe/London no longer has a no-op transition in January 1996.
1403
1404  Changes to build procedure
1405
1406    tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
1407    by a percent or so.
1408
1409  Changes to documentation and commentary
1410
1411    The Makefile now documents the POSIXRULES macro as being obsolete,
1412    and similarly, zic's -p POSIXRULES option is now documented as
1413    being obsolete.  Although the POSIXRULES feature still exists and
1414    works as before, in practice it is rarely used for its intended
1415    purpose, and it does not work either in the default reference
1416    implementation (for timestamps after 2037) or in common
1417    implementations such as GNU/Linux (for contemporary timestamps).
1418    Since POSIXRULES was designed primarily as a temporary transition
1419    facility for System V platforms that died off decades ago, it is
1420    being decommissioned rather than institutionalized.
1421
1422    New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
1423
1424
1425Release 2019a - 2019-03-25 22:01:33 -0700
1426
1427  Briefly:
1428    Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
1429    Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
1430
1431  Changes to past and future timestamps
1432
1433    Palestine will not start DST until 2019-03-30, instead of 2019-03-23 as
1434    previously predicted.  Adjust our prediction by guessing that spring
1435    transitions will be between 24 and 30 March, which matches recent practice
1436    since 2016.  (Thanks to Even Scharning and Tim Parenti.)
1437
1438    Metlakatla ended its observance of Pacific standard time,
1439    rejoining Alaska Time, on 2019-01-20 at 02:00.  (Thanks to Ryan
1440    Stanley and Tim Parenti.)
1441
1442  Changes to past timestamps
1443
1444    Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
1445    (Thanks to Alois Treindl and Isaac Starkman.)
1446
1447  Changes to time zone abbreviations
1448
1449    Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
1450    of being a separate zone that generates the abbreviation "UCT",
1451    which nowadays is typically a typo.  (Problem reported by Isiah
1452    Meadows.)
1453
1454  Changes to code
1455
1456    zic now has an -r option to limit the time range of output data.
1457    For example, 'zic -r @1000000000' limits the output data to
1458    timestamps starting 1000000000 seconds after the Epoch.
1459    This helps shrink output size and can be useful for applications
1460    not needing the full timestamp history, such as TZDIST truncation;
1461    see Internet RFC 8536 section 5.1.  (Inspired by a feature request
1462    from Christopher Wong, helped along by bug reports from Wong and
1463    from Tim Parenti.)
1464
1465  Changes to documentation
1466
1467    Mention Internet RFC 8536 (February 2019), which documents TZif.
1468
1469    tz-link.html now cites tzdata-meta
1470    <https://tzdata-meta.timtimeonline.com/>.
1471
1472
1473Release 2018i - 2018-12-30 11:05:43 -0800
1474
1475  Briefly:
1476    São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.
1477
1478  Changes to future timestamps
1479
1480    Due to a change in government, São Tomé and Príncipe switches back
1481    from +01 to +00 on 2019-01-01 at 02:00.  (Thanks to Vadim
1482    Nasardinov and Michael Deckers.)
1483
1484
1485Release 2018h - 2018-12-23 17:59:32 -0800
1486
1487  Briefly:
1488    Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
1489    New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
1490    Metlakatla, Alaska observes PST this winter only.
1491    Guess Morocco will continue to adjust clocks around Ramadan.
1492    Add predictions for Iran from 2038 through 2090.
1493
1494  Changes to future timestamps
1495
1496    Guess that Morocco will continue to fall back just before and
1497    spring forward just after Ramadan, the practice since 2012.
1498    (Thanks to Maamar Abdelkader.)  This means Morocco will observe
1499    negative DST during Ramadan in main and vanguard formats, and in
1500    rearguard format it stays in the +00 timezone and observes
1501    ordinary DST in all months other than Ramadan.  As before, extend
1502    this guesswork to the year 2037.  As a consequence, Morocco is
1503    scheduled to observe three DST transitions in some Gregorian years
1504    (e.g., 2033) due to the mismatch between the Gregorian and Islamic
1505    calendars.
1506
1507    The table of exact transitions for Iranian DST has been extended.
1508    It formerly cut off before the year 2038 in a nod to 32-bit time_t.
1509    It now cuts off before 2091 as there is doubt about how the Persian
1510    calendar will treat 2091.  This change predicts DST transitions in
1511    2038-9, 2042-3, and 2046-7 to occur one day later than previously
1512    predicted.  As before, post-cutoff transitions are approximated.
1513
1514  Changes to past and future timestamps
1515
1516    Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
1517    +05 on 2018-12-21.  This is a zone split as Qostanay (aka
1518    Kostanay) did not switch, so create a zone Asia/Qostanay.
1519
1520    Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
1521    It did not change clocks that day and remains on -08 this winter.
1522    (Thanks to Ryan Stanley.)  It will revert to the usual Alaska
1523    rules next spring, so this change affects only timestamps
1524    from 2018-11-04 through 2019-03-10.
1525
1526  Change to past timestamps
1527
1528    Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
1529    not 00:00.  I transcribed the time incorrectly from Shanks.
1530    (Thanks to Phake Nick.)
1531
1532    Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
1533    (Thanks to Phake Nick.)
1534
1535    Guam observed DST irregularly from 1959 through 1977.
1536    (Thanks to Phake Nick.)
1537
1538    Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
1539    10-01 changed standard time to +08:30 (not +08).  Its transition
1540    back to +08 after WWII was on 1945-09-15, not the previous day.
1541    Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
1542    (Thanks to Phake Nick, Steve Allen, and Joseph Myers.)  Also,
1543    its 1952 fallback was on 11-02 (not 10-25).
1544
1545    This release contains many changes to timestamps before 1946 due
1546    to Japanese possession or occupation of Pacific/Chuuk,
1547    Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
1548    Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
1549    (Thanks to Phake Nick.)
1550
1551    Assume that the Spanish East Indies was like the Philippines and
1552    observed American time until the end of 1844.  This affects
1553    Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.
1554
1555  Changes to past tm_isdst flags
1556
1557    For the recent Morocco change, the tm_isdst flag should be 1 from
1558    2018-10-27 00:00 to 2018-10-28 03:00.  (Thanks to Michael Deckers.)
1559    Give a URL to the official decree.  (Thanks to Matt Johnson.)
1560
1561
1562Release 2018g - 2018-10-26 22:22:45 -0700
1563
1564  Briefly:
1565    Morocco switches to permanent +01 on 2018-10-28.
1566
1567  Changes to future timestamps
1568
1569    Morocco switches from +00/+01 to permanent +01 effective 2018-10-28,
1570    so its clocks will not fall back as previously scheduled.
1571    (Thanks to Mohamed Essedik Najd and Brian Inglis.)
1572
1573  Changes to code
1574
1575    When generating TZif files with leap seconds, zic no longer uses a
1576    format that trips up older 32-bit clients, fixing a bug introduced
1577    in 2018f.  (Reported by Daniel Fischer.)  Also, the zic workaround
1578    for QTBUG-53071 now also works for TZif files with leap seconds.
1579
1580    The translator to rearguard format now rewrites the line
1581    "Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S" to
1582    "Rule Japan 1948 1951 - Sep Sun>=9  1:00 0 S".
1583    This caters to zic before 2007 and to Oracle TZUpdater 2.2.0
1584    and earlier.  (Reported by Christos Zoulas.)
1585
1586  Changes to past time zone abbreviations
1587
1588    Change HDT to HWT/HPT for WWII-era abbreviations in Hawaii.
1589    This reverts to 2011h, as the abbreviation change in 2011i was
1590    likely inadvertent.
1591
1592  Changes to documentation
1593
1594    tzfile.5 has new sections on interoperability issues.
1595
1596
1597Release 2018f - 2018-10-18 00:14:18 -0700
1598
1599  Briefly:
1600  Volgograd moves from +03 to +04 on 2018-10-28.
1601  Fiji ends DST 2019-01-13, not 2019-01-20.
1602  Most of Chile changes DST dates, effective 2019-04-06.
1603
1604  Changes to future timestamps
1605
1606    Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
1607    (Thanks to Alexander Fetisov and Stepan Golosunov.)
1608
1609    Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
1610    predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
1611    accordingly.
1612
1613    Most of Chile will end DST on the first Saturday in April at 24:00 mainland
1614    time, and resume DST on the first Saturday in September at 24:00 mainland
1615    time.  The changes are effective from 2019-04-06, and do not affect the
1616    Magallanes region modeled by America/Punta_Arenas.  (Thanks to Juan Correa
1617    and Tim Parenti.)  Adjust future predictions accordingly.
1618
1619  Changes to past timestamps
1620
1621    The 2018-05-05 North Korea 30-minute time zone change took place
1622    at 23:30 the previous day, not at 00:00 that day.
1623
1624    China's 1988 spring-forward transition was on April 17, not
1625    April 10.  Its DST transitions in 1986/91 were at 02:00, not 00:00.
1626    (Thanks to P Chan.)
1627
1628    Fix several issues for Macau before 1992.  Macau's pre-1904 LMT
1629    was off by 10 s.  Macau switched to +08 in 1904 not 1912, and
1630    temporarily switched to +09/+10 during World War II.  Macau
1631    observed DST in 1942/79, not 1961/80, and there were several
1632    errors for transition times and dates.  (Thanks to P Chan.)
1633
1634    The 1948-1951 fallback transitions in Japan were at 25:00 on
1635    September's second Saturday, not at 24:00.  (Thanks to Phake Nick.)
1636    zic turns this into 01:00 on the day after September's second
1637    Saturday, which is the best that POSIX or C platforms can do.
1638
1639    Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
1640    paper by Li Yu, replacing more-questionable data from Shanks.
1641
1642  Changes to time zone abbreviations
1643
1644    Use "PST" and "PDT" for Philippine time.  (Thanks to Paul Goyette.)
1645
1646  Changes to code
1647
1648    zic now always generates TZif files where time type 0 is used for
1649    timestamps before the first transition.  This simplifies the
1650    reading of TZif files and should not affect behavior of existing
1651    TZif readers because the same set of time types is used; only
1652    their internal indexes may have changed.  This affects only the
1653    legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
1654    EET, which previously used nonzero types for these timestamps.
1655
1656    Because of the type 0 change, zic no longer outputs a dummy
1657    transition at time -2**59 (before the Big Bang), as clients should
1658    no longer need this to handle historical timestamps correctly.
1659    This reverts a change introduced in 2013d and shrinks most TZif
1660    files by a few bytes.
1661
1662    zic now supports negative time-of-day in Rule and Leap lines, e.g.,
1663    "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
1664    occurs at 18:00 on the Saturday before the last Sunday in April.
1665    This behavior was documented in 2018a but the code did not
1666    entirely match the documentation.
1667
1668    localtime.c no longer requires at least one time type in TZif
1669    files that lack transitions or have a POSIX-style TZ string.  This
1670    future-proofs the code against possible future extensions to the
1671    format that would allow TZif files with POSIX-style TZ strings and
1672    without transitions or time types.
1673
1674    A read-access subscript error in localtime.c has been fixed.
1675    It could occur only in TZif files with timecnt == 0, something that
1676    does not happen in practice now but could happen in future versions.
1677
1678    localtime.c no longer ignores TZif POSIX-style TZ strings that
1679    specify only standard time.  Instead, these TZ strings now
1680    override the default time type for timestamps after the last
1681    transition (or for all timestamps if there are no transitions),
1682    just as DST strings specifying DST have always done.
1683
1684    leapseconds.awk now outputs "#updated" and "#expires" comments,
1685    and supports leap seconds at the ends of months other than June
1686    and December.  (Inspired by suggestions from Chris Woodbury.)
1687
1688  Changes to documentation
1689
1690    New restrictions: A Rule name must start with a character that
1691    is neither an ASCII digit nor "-" nor "+", and an unquoted name
1692    should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
1693    The latter restriction makes room for future extensions (a
1694    possibility noted by Tom Lane).
1695
1696    tzfile.5 now documents what time types apply before the first and
1697    after the last transition, if any.
1698
1699    Documentation now uses the spelling "timezone" for a TZ setting
1700    that determines timestamp history, and "time zone" for a
1701    geographic region currently sharing the same standard time.
1702
1703    The name "TZif" is now used for the tz binary data format.
1704
1705    tz-link.htm now mentions the A0 TimeZone Migration utilities.
1706    (Thanks to Aldrin Martoq for the link.)
1707
1708  Changes to build procedure
1709
1710    New 'make' target 'rearguard_tarballs' to build the rearguard
1711    tarball only.  This is a convenience on platforms that lack lzip
1712    if you want to build the rearguard tarball.  (Problem reported by
1713    Deborah Goldsmith.)
1714
1715    tzdata.zi is now more stable from release to release.  (Problem
1716    noted by Tom Lane.)  It is also a bit shorter.
1717
1718    tzdata.zi now can contain comment lines documenting configuration
1719    information, such as which data format was selected, which input
1720    files were used, and how leap seconds are treated.  (Problems
1721    noted by Lester Caine and Brian Inglis.)  If the Makefile defaults
1722    are used these comment lines are absent, for backward
1723    compatibility.  A redistributor intending to alter its copy of the
1724    files should also append "-LABEL" to the 'version' file's first
1725    line, where "LABEL" identifies the redistributor's change.
1726
1727
1728Release 2018e - 2018-05-01 23:42:51 -0700
1729
1730  Briefly:
1731
1732    North Korea switches back to +09 on 2018-05-05.
1733    The main format uses negative DST again, for Ireland etc.
1734    'make tarballs' now also builds a rearguard tarball.
1735    New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
1736
1737  Changes to past and future timestamps
1738
1739    North Korea switches back from +0830 to +09 on 2018-05-05.
1740    (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
1741    and Tim Parenti.)
1742
1743    Bring back the negative-DST changes of 2018a, except be more
1744    compatible with data parsers that do not support negative DST.
1745    Also, this now affects historical timestamps in Namibia and the
1746    former Czechoslovakia, not just Ireland.  The main format now uses
1747    negative DST to model timestamps in Europe/Dublin (from 1971 on),
1748    Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
1749    does not affect UT offsets, only time zone abbreviations and the
1750    tm_isdst flag.  Also, this does not affect rearguard or vanguard
1751    formats; effectively the main format now uses vanguard instead of
1752    rearguard format.  Data parsers that do not support negative DST
1753    can still use data from the rearguard tarball described below.
1754
1755  Changes to build procedure
1756
1757    The command 'make tarballs' now also builds the tarball
1758    tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
1759    except that it uses rearguard format intended for trailing-edge
1760    data parsers.
1761
1762  Changes to data format and to code
1763
1764    The SAVE column of Rule and Zone lines can now have an 's' or 'd'
1765    suffix, which specifies whether the adjusted time is standard time
1766    or daylight saving time.  If no suffix is given, daylight saving
1767    time is used if and only if the SAVE column is nonzero; this is
1768    the longstanding behavior.  Although this new feature is not used
1769    in tzdata, it could be used to specify the legal time in Namibia
1770    1994-2017, as opposed to the popular time (see below).
1771
1772  Changes to past timestamps
1773
1774    From 1994 through 2017 Namibia observed DST in winter, not summer.
1775    That is, it used negative DST, as Ireland still does.  This change
1776    does not affect UTC offsets; it affects only the tm_isdst flag and
1777    the abbreviation used during summer, which is now CAT, not WAST.
1778    Although (as noted by Michael Deckers) summer and winter time were
1779    both simply called "standard time" in Namibian law, in common
1780    practice winter time was considered to be DST (as noted by Stephen
1781    Colebourne).  The full effect of this change is only in vanguard
1782    and main format; in rearguard format, the tm_isdst flag is still
1783    zero in winter and nonzero in summer.
1784
1785    In 1946/7 Czechoslovakia also observed negative DST in winter.
1786    The full effect of this change is only in vanguard and main
1787    formats; in rearguard format, it is modeled as plain GMT without
1788    daylight saving.  Also, the dates of some 1944/5 DST transitions
1789    in Czechoslovakia have been changed.
1790
1791
1792Release 2018d - 2018-03-22 07:05:46 -0700
1793
1794  Briefly:
1795
1796  Palestine starts DST a week earlier in 2018.
1797  Add support for vanguard and rearguard data consumers.
1798  Add subsecond precision to source data format, though not to data.
1799
1800  Changes to future timestamps
1801
1802    In 2018, Palestine starts DST on March 24, not March 31.
1803    Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
1804
1805  Changes to past and future timestamps
1806
1807    Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
1808    at 04:00.  (Thanks to Steffen Thorsen.)
1809
1810  Changes to past timestamps
1811
1812    Historical transitions for Uruguay, represented by
1813    America/Montevideo, have been updated per official legal documents,
1814    replacing previous data mainly originating from the inventions of
1815    Shanks & Pottenger.  This has resulted in adjustments ranging from
1816    30 to 90 minutes in either direction over at least two dozen
1817    distinct periods ranging from one day to several years in length.
1818    A mere handful of pre-1991 transitions are unaffected; data since
1819    then has come from more reliable contemporaneous reporting.  These
1820    changes affect various timestamps in 1920-1923, 1936, 1939,
1821    1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
1822    Additionally, Uruguay's pre-standard-time UT offset has been
1823    adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
1824    match the location of the Observatory of the National Meteorological
1825    Institute in Montevideo.
1826    (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
1827
1828    East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
1829    (Thanks to Kerry Shetline.)
1830
1831    Fix the 1912-01-01 transition for Portugal and its colonies.
1832    This transition was at 00:00 according to the new UT offset, not
1833    according to the old one.  Also assume that Cape Verde switched on
1834    the same date as the rest, not in 1907.  This affects
1835    Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
1836    Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
1837    (Thanks to Michael Deckers.)
1838
1839    Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
1840    Turks & Caicos.
1841
1842  Changes to past time zone abbreviations
1843
1844    MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
1845    is no clock change associated with the transition.
1846
1847  Changes to build procedure
1848
1849    The new DATAFORM macro in the Makefile lets the installer choose
1850    among three source data formats.  The idea is to lessen downstream
1851    disruption when data formats are improved.
1852
1853    * DATAFORM=vanguard installs from the latest, bleeding-edge
1854      format.  DATAFORM=main (the default) installs from the format
1855      used in the 'africa' etc. files.  DATAFORM=rearguard installs
1856      from a trailing-edge format.  Eventually, elements of today's
1857      vanguard format should move to the main format, and similarly
1858      the main format's features should eventually move to the
1859      rearguard format.
1860
1861    * In the current version, the main and rearguard formats are
1862      identical and match that of 2018c, so this change does not
1863      affect default behavior.  The vanguard format currently contains
1864      one feature not in the main format: negative SAVE values.  This
1865      improves support for Ireland, which uses Irish Standard Time
1866      (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
1867      supported negative SAVE values for decades, and this feature
1868      should move to the main format soon.  However, it will not move
1869      to the rearguard format for quite some time because some
1870      downstream parsers do not support it.
1871
1872    * The build procedure constructs three files vanguard.zi, main.zi,
1873      and rearguard.zi, one for each format.  Although the files
1874      represent essentially the same data, they may have minor
1875      discrepancies that users are not likely to notice.  The files
1876      are intended for downstream data consumers and are not
1877      installed.  Zoneinfo parsers that do not support negative SAVE values
1878      should start using rearguard.zi, so that they will be unaffected
1879      when the negative-DST feature moves from vanguard to main.
1880      Bleeding-edge Zoneinfo parsers that support the new features
1881      already can use vanguard.zi; in this respect, current tzcode is
1882      bleeding-edge.
1883
1884    The Makefile should now be safe for parallelized builds, and 'make
1885    -j to2050new.tzs' is now much faster on a multiprocessor host
1886    with GNU Make.
1887
1888    When built with -DSUPPRESS_TZDIR, the tzcode library no longer
1889    prepends TZDIR/ to file names that do not begin with '/'.  This is
1890    not recommended for general use, due to its security implications.
1891    (From a suggestion by Manuela Friedrich.)
1892
1893  Changes to code
1894
1895    zic now accepts subsecond precision in expressions like
1896    00:19:32.13, which is approximately the legal time of the
1897    Netherlands from 1835 to 1937.  However, because it is
1898    questionable whether the few recorded uses of non-integer offsets
1899    had subsecond precision in practice, there are no plans for tzdata
1900    to use this feature.  (Thanks to Steve Allen for pointing out
1901    the limitations of historical data in this area.)
1902
1903    The code is a bit more portable to MS-Windows.  Installers can
1904    compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
1905    reserve identifiers like 'localtime'.  (Thanks to Manuela
1906    Friedrich.)
1907
1908  Changes to documentation and commentary
1909
1910    theory.html now outlines tzdb's extensions to POSIX's model for
1911    civil time, and has a section "POSIX features no longer needed"
1912    that lists POSIX API components that are now vestigial.
1913    (From suggestions by Steve Summit.)  It also better distinguishes
1914    time zones from tz regions.  (From a suggestion by Guy Harris.)
1915
1916    Commentary is now more consistent about using the phrase "daylight
1917    saving time", to match the C name tm_isdst.  Daylight saving time
1918    need not occur in summer, and need not have a positive offset from
1919    standard time.
1920
1921    Commentary about historical transitions in Uruguay has been expanded
1922    with links to many relevant legal documents.
1923    (Thanks to Tim Parenti.)
1924
1925    Commentary now uses some non-ASCII characters with Unicode value
1926    less than U+0100, as they can be useful and should work even with
1927    older editors such as XEmacs.
1928
1929
1930Release 2018c - 2018-01-22 23:00:44 -0800
1931
1932  Briefly:
1933  Revert Irish changes that relied on negative SAVE values.
1934
1935  Changes to tm_isdst
1936
1937    Revert the 2018a change to Europe/Dublin.  As before, this change
1938    does not affect UT offsets or abbreviations; it affects only
1939    whether timestamps are considered to be standard time or
1940    daylight-saving time, as expressed in the tm_isdst flag of C's
1941    struct tm type.  This reversion is intended to be a temporary
1942    workaround for problems discovered with downstream uses of
1943    releases 2018a and 2018b, which implemented Irish time by using
1944    negative SAVE values in the Eire rules of the 'europe' file.
1945    Although negative SAVE values have been part of tzcode for many
1946    years and are supported by many platforms, they were not
1947    documented before 2018a and ICU and OpenJDK do not currently
1948    support them.  A mechanism to export data to platforms lacking
1949    support for negative DST is planned to be developed before the
1950    change is reapplied.  (Problems reported by Deborah Goldsmith and
1951    Stephen Colebourne.)
1952
1953  Changes to past timestamps
1954
1955    Japanese DST transitions (1948-1951) were Sundays at 00:00, not
1956    Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
1957
1958  Changes to build procedure
1959
1960    The build procedure now works around mawk 1.3.3's lack of support
1961    for character class expressions.  (Problem reported by Ohyama.)
1962
1963
1964Release 2018b - 2018-01-17 23:24:48 -0800
1965
1966  Briefly:
1967  Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
1968
1969  Changes to build procedure
1970
1971    The distribution now contains the file 'pacificnew' again.
1972    This file was inadvertently omitted in the 2018a distribution.
1973    (Problem reported by Matias Fonzo.)
1974
1975
1976Release 2018a - 2018-01-12 22:29:21 -0800
1977
1978  Briefly:
1979  São Tomé and Príncipe switched from +00 to +01.
1980  Brazil's DST will now start on November's first Sunday.
1981  Ireland's standard time is now in the summer, not the winter.
1982  Use Debian-style installation locations, instead of 4.3BSD-style.
1983  New zic option -t.
1984
1985  Changes to past and future timestamps
1986
1987    São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
1988    01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
1989
1990  Changes to future timestamps
1991
1992    Starting in 2018 southern Brazil will begin DST on November's
1993    first Sunday instead of October's third Sunday.  (Thanks to
1994    Steffen Thorsen.)
1995
1996  Changes to past timestamps
1997
1998    A discrepancy of 4 s in timestamps before 1931 in South Sudan has
1999    been corrected.  The 'backzone' and 'zone.tab' files did not agree
2000    with the 'africa' and 'zone1970.tab' files.  (Problem reported by
2001    Michael Deckers.)
2002
2003    The abbreviation invented for Bolivia Summer Time (1931-2) is now
2004    BST instead of BOST, to be more consistent with the convention
2005    used for Latvian Summer Time (1918-9) and for British Summer Time.
2006
2007  Changes to tm_isdst
2008
2009    Change Europe/Dublin so that it observes Irish Standard Time (UT
2010    +01) in summer and GMT (as negative daylight-saving) in winter,
2011    instead of observing standard time (GMT) in winter and Irish
2012    Summer Time (UT +01) in summer.  This change does not affect UT
2013    offsets or abbreviations; it affects only whether timestamps are
2014    considered to be standard time or daylight-saving time, as
2015    expressed in the tm_isdst flag of C's struct tm type.
2016    (Discrepancy noted by Derick Rethans.)
2017
2018  Changes to build procedure
2019
2020    The default installation locations have been changed to mostly
2021    match Debian circa 2017, instead of being designed as an add-on to
2022    4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
2023    TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
2024    USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
2025    locations more precisely.  (This responds to suggestions from
2026    Brian Inglis and from Steve Summit.)
2027
2028    The default installation procedure no longer creates the
2029    backward-compatibility link US/Pacific-New, which causes
2030    confusion during user setup (e.g., see Debian bug 815200).
2031    Use 'make BACKWARD="backward pacificnew"' to create the link
2032    anyway, for now.  Eventually we plan to remove the link entirely.
2033
2034    tzdata.zi now contains a version-number comment.
2035    (Suggested by Tom Lane.)
2036
2037    The Makefile now quotes values like BACKWARD more carefully when
2038    passing them to the shell.  (Problem reported by Zefram.)
2039
2040    Builders no longer need to specify -DHAVE_SNPRINTF on platforms
2041    that have snprintf and use pre-C99 compilers.  (Problem reported
2042    by Jon Skeet.)
2043
2044  Changes to code
2045
2046    zic has a new option -t FILE that specifies the location of the
2047    file that determines local time when TZ is unset.  The default for
2048    this location can be configured via the new TZDEFAULT makefile
2049    macro, which defaults to /etc/localtime.
2050
2051    Diagnostics and commentary now distinguish UT from UTC more
2052    carefully; see theory.html for more information about UT vs UTC.
2053
2054    zic has been ported to GCC 8's -Wstringop-truncation option.
2055    (Problem reported by Martin Sebor.)
2056
2057  Changes to documentation and commentary
2058
2059    The zic man page now documents the longstanding behavior that
2060    times and years can be out of the usual range, with negative times
2061    counting backwards from midnight and with year 0 preceding year 1.
2062    (Problem reported by Michael Deckers.)
2063
2064    The theory.html file now mentions the POSIX limit of six chars
2065    per abbreviation, and lists alphabetic abbreviations used.
2066
2067    The files tz-art.htm and tz-link.htm have been renamed to
2068    tz-art.html and tz-link.html, respectively, for consistency with
2069    other file names and to simplify web server configuration.
2070
2071
2072Release 2017c - 2017-10-20 14:49:34 -0700
2073
2074  Briefly:
2075  Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
2076  Fiji ends DST 2018-01-14, not 2018-01-21.
2077  Namibia switches from +01/+02 to +02 on 2018-04-01.
2078  Sudan switches from +03 to +02 on 2017-11-01.
2079  Tonga likely switches from +13/+14 to +13 on 2017-11-05.
2080  Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
2081  A new file tzdata.zi now holds a small text copy of all data.
2082  The zic input format has been regularized slightly.
2083
2084  Changes to future timestamps
2085
2086    Northern Cyprus has decided to resume EU rules starting
2087    2017-10-29, thus reinstituting winter time.
2088
2089    Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
2090    predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
2091    accordingly.
2092
2093    Namibia will switch from +01 with DST to +02 all year on
2094    2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
2095    at 02:00.  (Thanks to Steffen Thorsen.)
2096
2097    Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
2098    Atyya and Yahia Abdalla.)  South Sudan is not switching, so
2099    Africa/Juba is no longer a link to Africa/Khartoum.
2100
2101    Tonga has likely ended its experiment with DST, and will not
2102    adjust its clocks on 2017-11-05.  Although Tonga has not announced
2103    whether it will continue to observe DST, the IATA is assuming that
2104    it will not.  (Thanks to David Wade.)
2105
2106    Turks & Caicos will switch from -04 all year to -05 with US DST on
2107    2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
2108    at 02:00.  (Thanks to Steffen Thorsen.)
2109
2110  Changes to past timestamps
2111
2112    Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
2113    (Thanks to Arthur David Olson.)
2114
2115    Detroit did not observe DST in 1967.
2116
2117    Use railway time for Asia/Kolkata before 1941, by switching to
2118    Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
2119    1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
2120
2121    Europe/Dublin's 1946 and 1947 fallback transitions occurred at
2122    02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
2123
2124    Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
2125    American time in 1892, not 1879.  (Thanks to Michael Deckers.)
2126
2127    Adjust the 1867 transition in Alaska to better reflect the
2128    historical record, by changing it to occur on 1867-10-18 at 15:30
2129    Sitka time rather than at the start of 1867-10-17 local time.
2130    Although strictly speaking this is accurate only for Sitka,
2131    the rest of Alaska's blanks need to be filled in somehow.
2132
2133    Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
2134    (Thanks to Michael Deckers.)
2135
2136    Add 7 s to the UT offset in Asia/Yangon before 1920.
2137
2138  Changes to zone names
2139
2140    Remove Canada/East-Saskatchewan from the 'backward' file, as it
2141    exceeded the 14-character limit and was an unused misnomer anyway.
2142
2143  Changes to build procedure
2144
2145    To support applications that prefer to read time zone data in text
2146    form, two zic input files tzdata.zi and leapseconds are now
2147    installed by default.  The commands 'zic tzdata.zi' and 'zic -L
2148    leapseconds tzdata.zi' can reproduce the tzdata binary files
2149    without and with leap seconds, respectively.  To prevent these two
2150    new files from being installed, use 'make TZDATA_TEXT=', and to
2151    suppress leap seconds from the tzdata text installation, use 'make
2152    TZDATA_TEXT=tzdata.zi'.
2153
2154    'make BACKWARD=' now suppresses backward-compatibility names
2155    like 'US/Pacific' that are defined in the 'backward' and
2156    'pacificnew' files.
2157
2158    'make check' now works on systems that lack a UTF-8 locale,
2159    or that lack the nsgmls program.  Set UTF8_LOCALE to configure
2160    the name of a UTF-8 locale, if you have one.
2161
2162    Y2K runtime checks are no longer enabled by default.  Add
2163    -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
2164    adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
2165    to disable them.  (New name suggested by Brian Inglis.)
2166
2167    The build procedure for zdump now works on AIX 7.1.
2168    (Problem reported by Kees Dekker.)
2169
2170  Changes to code
2171
2172    zic and the reference runtime now reject multiple leap seconds
2173    within 28 days of each other, or leap seconds before the Epoch.
2174    As a result, support for double leap seconds, which was
2175    obsolescent and undocumented, has been removed.  Double leap
2176    seconds were an error in the C89 standard; they have never existed
2177    in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
2178    noticing glitches in the code that uncovered this problem.)
2179
2180    zic now warns about use of the obsolescent and undocumented -y
2181    option, and about use of the obsolescent TYPE field of Rule lines.
2182
2183    zic now allows unambiguous abbreviations like "Sa" and "Su" for
2184    weekdays; formerly it rejected them due to a bug.  Conversely, zic
2185    no longer considers non-prefixes to be abbreviations; for example,
2186    it no longer accepts "lF" as an abbreviation for "lastFriday".
2187    Also, zic warns about the undocumented usage with a "last-"
2188    prefix, e.g., "last-Fri".
2189
2190    Similarly, zic now accepts the unambiguous abbreviation "L" for
2191    "Link" in ordinary context and for "Leap" in leap-second context.
2192    Conversely, zic no longer accepts non-prefixes such as "La" as
2193    abbreviations for words like "Leap".
2194
2195    zic no longer accepts leap second lines in ordinary input, or
2196    ordinary lines in leap second input.  Formerly, zic sometimes
2197    warned about this undocumented usage and handled it incorrectly.
2198
2199    The new macro HAVE_TZNAME governs whether the tzname external
2200    variable is exported, instead of USG_COMPAT.  USG_COMPAT now
2201    governs only the external variables "timezone" and "daylight".
2202    This change is needed because the three variables are not in the
2203    same category: although POSIX requires tzname, it specifies the
2204    other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
2205    if not defined, the code attempts to guess it from other macros.
2206
2207    localtime.c and difftime.c no longer require stdio.h, and .c files
2208    other than zic.c no longer require sys/wait.h.
2209
2210    zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
2211
2212    Calculation of time_t extrema works around a bug in GCC 4.8.4
2213    (Reported by Stan Shebs and Joseph Myers.)
2214
2215    zic.c no longer mistranslates formats of line numbers in non-English
2216    locales.  (Problem reported by Benno Schulenberg.)
2217
2218    Several minor changes have been made to the code to make it a
2219    bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
2220    Dekker for reporting the problems.)
2221
2222  Changes to documentation and commentary
2223
2224    The two new files 'theory.html' and 'calendars' contain the
2225    contents of the removed file 'Theory'.  The goal is to document
2226    tzdb theory more accessibly.
2227
2228    The zic man page now documents abbreviation rules.
2229
2230    tz-link.htm now covers how to apply tzdata changes to clients.
2231    (Thanks to Jorge Fábregas for the AIX link.)  It also mentions MySQL.
2232
2233    The leap-seconds.list URL has been updated to something that is
2234    more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
2235
2236Release 2017b - 2017-03-17 07:30:38 -0700
2237
2238  Briefly: Haiti has resumed DST.
2239
2240  Changes to past and future timestamps
2241
2242    Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
2243
2244  Changes to past timestamps
2245
2246    Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
2247
2248    Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
2249    is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
2250
2251  Changes to code
2252
2253    The reference localtime implementation now falls back on the
2254    current US daylight-saving transition rules rather than the
2255    1987-2006 rules.  This fallback occurs only when (1) the TZ
2256    environment variable has a value like "AST4ADT" that asks
2257    for daylight saving time but does not specify the rules, (2) there
2258    is no file by that name, and (3) the TZDEFRULES file cannot be
2259    loaded.  (Thanks to Tom Lane.)
2260
2261
2262Release 2017a - 2017-02-28 00:05:36 -0800
2263
2264  Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
2265  discontinues DST.
2266
2267  Changes to future timestamps
2268
2269    Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
2270
2271    Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
2272    Its clocks diverge from America/Santiago starting 2017-05-13 at
2273    23:00, hiving off a new zone America/Punta_Arenas.  Although the
2274    Chilean government says this change expires in May 2019, for now
2275    assume it's permanent.  (Thanks to Juan Correa and Deborah
2276    Goldsmith.)  This also affects Antarctica/Palmer.
2277
2278  Changes to past timestamps
2279
2280    Fix many entries for historical timestamps for Europe/Madrid
2281    before 1979, to agree with tables compiled by Pere Planesas of the
2282    National Astronomical Observatory of Spain.  As a side effect,
2283    this changes some timestamps for Africa/Ceuta before 1929, which
2284    are probably guesswork anyway.  (Thanks to Steve Allen and
2285    Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
2286    correcting the 1901 transition.)
2287
2288    Ecuador observed DST from 1992-11-28 to 1993-02-05.
2289    (Thanks to Alois Treindl.)
2290
2291    Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
2292    (Thanks to Stepan Golosunov.)
2293
2294  Changes to past and future time zone abbreviations
2295
2296    Switch to numeric time zone abbreviations for South America, as
2297    part of the ongoing project of removing invented abbreviations.
2298    This avoids the need to invent an abbreviation for the new Chilean
2299    new zone.  Similarly, switch from invented to numeric time zone
2300    abbreviations for Afghanistan, American Samoa, the Azores,
2301    Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
2302    Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
2303    Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
2304    Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
2305    the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
2306    Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
2307    Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
2308    Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
2309    Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
2310    Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
2311    for half-hour daylight saving time in Belize before 1944 and in
2312    the Dominican Republic before 1975; and for Canary Islands before
2313    1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
2314    Indian Summer Time before 1942, for Indonesia before around 1964,
2315    for Kenya before 1960, for Liberia before 1973, for Madeira before
2316    1967, for Namibia before 1943, for the Netherlands in 1937-9, for
2317    Pakistan before 1971, for Western Sahara before 1977, and for
2318    Zaporozhye in 1880-1924.
2319
2320    For Alaska time from 1900 through 1967, instead of "CAT" use the
2321    abbreviation "AST", the abbreviation commonly used at the time
2322    (Atlantic Standard Time had not been standardized yet).  Use "AWT"
2323    and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
2324
2325    Use "CST" and "CDT" instead of invented abbreviations for Macau
2326    before 1999 and Taiwan before 1938, and use "JST" instead of the
2327    invented abbreviation "JCST" for Japan and Korea before 1938.
2328
2329  Change to database entry category
2330
2331    Move the Pacific/Johnston link from 'australasia' to 'backward',
2332    since Johnston is now uninhabited.
2333
2334  Changes to code
2335
2336    zic no longer mishandles some transitions in January 2038 when it
2337    attempts to work around Qt bug 53071.  This fixes a bug affecting
2338    Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
2339    now contains a workaround, useful when loading a file generated by
2340    a buggy zic.  (Problem and localtime.c fix reported by Bradley
2341    White.)
2342
2343    zdump -i now outputs non-hour numeric time zone abbreviations
2344    without a colon, e.g., "+0530" rather than "+05:30".  This agrees
2345    with zic %z and with common practice, and simplifies auditing of
2346    zdump output.
2347
2348    zdump is now buildable again with -DUSE_LTZ=0.
2349    (Problem reported by Joseph Myers.)
2350
2351    zdump.c now always includes private.h, to avoid code duplication
2352    with private.h.  (Problem reported by Kees Dekker.)
2353
2354    localtime.c no longer mishandles early or late timestamps
2355    when TZ is set to a POSIX-style string that specifies DST.
2356    (Problem reported by Kees Dekker.)
2357
2358    date and strftime now cause %z to generate "-0000" instead of
2359    "+0000" when the UT offset is zero and the time zone abbreviation
2360    begins with "-".
2361
2362  Changes to documentation and commentary
2363
2364    The 'Theory' file now better documents choice of historical time
2365    zone abbreviations.  (Problems reported by Michael Deckers.)
2366
2367    tz-link.htm now covers leap smearing, which is popular in clouds.
2368
2369
2370Release 2016j - 2016-11-22 23:17:13 -0800
2371
2372  Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
2373
2374  Changes to future timestamps
2375
2376    Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
2377    This hives off a new zone Europe/Saratov from Europe/Volgograd.
2378    (Thanks to Yuri Konotopov and Stepan Golosunov.)
2379
2380  Changes to past timestamps
2381
2382    The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
2383    Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
2384    1999, not fall 1994.  (Thanks to Stepan Golosunov.)
2385
2386  Changes to past time zone abbreviations
2387
2388    Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
2389    summer time before 1948.  The old use of "EET" was a typo.
2390
2391  Changes to code
2392
2393    zic no longer mishandles file systems that lack hard links, fixing
2394    bugs introduced in 2016g.  (Problems reported by Tom Lane.)
2395    Also, when the destination already contains symbolic links, zic
2396    should now work better on systems where the 'link' system call
2397    does not follow symbolic links.
2398
2399  Changes to documentation and commentary
2400
2401    tz-link.htm now documents the relationship between release version
2402    numbers and development-repository commit tags.  (Suggested by
2403    Paul Koning.)
2404
2405    The 'Theory' file now documents UT.
2406
2407    iso3166.tab now accents "Curaçao", and commentary now mentions
2408    the names "Cabo Verde" and "Czechia".  (Thanks to Jiří Boháč.)
2409
2410
2411Release 2016i - 2016-11-01 23:19:52 -0700
2412
2413  Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
2414  reintroduces DST on 2016-11-06.
2415
2416  Changes to future timestamps
2417
2418    Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
2419    2017-01-15 at 03:00.  Assume future observances in Tonga will be
2420    from the first Sunday in November through the third Sunday in
2421    January, like Fiji.  (Thanks to Pulu ʻAnau.)  Switch to numeric
2422    time zone abbreviations for this zone.
2423
2424  Changes to past and future timestamps
2425
2426    Northern Cyprus is now +03 year round, causing a split in Cyprus
2427    time zones starting 2016-10-30 at 04:00.  This creates a zone
2428    Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
2429
2430    Antarctica/Casey switched from +08 to +11 on 2016-10-22.
2431    (Thanks to Steffen Thorsen.)
2432
2433  Changes to past timestamps
2434
2435    Several corrections were made for pre-1975 timestamps in Italy.
2436    These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
2437    Europe/Vatican.
2438
2439    First, the 1893-11-01 00:00 transition in Italy used the new UT
2440    offset (+01), not the old (+00:49:56).  (Thanks to Michael
2441    Deckers.)
2442
2443    Second, rules for daylight saving in Italy were changed to agree
2444    with Italy's National Institute of Metrological Research (INRiM)
2445    except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
2446    Inglis, and Michael Deckers):
2447
2448      The 1916-06-03 transition was at 24:00, not 00:00.
2449
2450      The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
2451      00:00, not 01:00.
2452
2453      The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
2454      01:00.
2455
2456      The 1944-09-17 transition was at 03:00, not 01:00.  This
2457      particular change is taken from Italian law as INRiM's table,
2458      (which says 02:00) appears to have a typo here.  Also, keep the
2459      1944-04-03 transition for Europe/Rome, as Rome was controlled by
2460      Germany then.
2461
2462      The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
2463      not 00:00.
2464
2465  Changes to code
2466
2467    The code should now be buildable on AmigaOS merely by setting the
2468    appropriate Makefile variables.  (From a patch by Carsten Larsen.)
2469
2470
2471Release 2016h - 2016-10-19 23:17:57 -0700
2472
2473  Changes to future timestamps
2474
2475    Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
2476    2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
2477    future fall transitions will be on the last Saturday of October
2478    at 01:00, which is consistent with predicted spring transitions
2479    on the last Saturday of March.  (Thanks to Tim Parenti.)
2480
2481  Changes to past timestamps
2482
2483    In Turkey, transitions in 1986-1990 were at 01:00 standard time
2484    not at 02:00, and the spring 1994 transition was on March 20, not
2485    March 27.  (Thanks to Kıvanç Yazan.)
2486
2487  Changes to past and future time zone abbreviations
2488
2489    Asia/Colombo now uses numeric time zone abbreviations like "+0530"
2490    instead of alphabetic ones like "IST" and "LKT".  Various
2491    English-language sources use "IST", "LKT" and "SLST", with no
2492    working consensus.  (Usage of "SLST" mentioned by Sadika
2493    Sumanapala.)
2494
2495  Changes to code
2496
2497    zic no longer mishandles relativizing file names when creating
2498    symbolic links like /etc/localtime, when these symbolic links
2499    are outside the usual directory hierarchy.  This fixes a bug
2500    introduced in 2016g.  (Problem reported by Andreas Stieger.)
2501
2502  Changes to build procedure
2503
2504    New rules 'traditional_tarballs' and 'traditional_signatures' for
2505    building just the traditional-format distribution.  (Requested by
2506    Deborah Goldsmith.)
2507
2508    The file 'version' is now put into the tzdata tarball too.
2509    (Requested by Howard Hinnant.)
2510
2511  Changes to documentation and commentary
2512
2513    The 'Theory' file now has a section on interface stability.
2514    (Requested by Paul Koning.)  It also mentions features like
2515    tm_zone and localtime_rz that have long been supported by the
2516    reference code.
2517
2518    tz-link.htm has improved coverage of time zone boundaries suitable
2519    for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
2520    Johnson.)
2521
2522    The US commentary now mentions Allen and the "day of two noons".
2523
2524    The Fiji commentary mentions the government's 2016-10-03 press
2525    release.  (Thanks to Raymond Kumar.)
2526
2527
2528Release 2016g - 2016-09-13 08:56:38 -0700
2529
2530  Changes to future timestamps
2531
2532    Turkey switched from EET/EEST (+02/+03) to permanent +03,
2533    effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
2534    than an invented abbreviation for the new time.
2535
2536    New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
2537    (Thanks to Tim Parenti.)
2538
2539  Changes to past timestamps
2540
2541    For America/Los_Angeles, spring-forward transition times have been
2542    corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
2543    1950-1966.
2544
2545    For zones using Soviet time on 1919-07-01, transitions to UT-based
2546    time were at 00:00 UT, not at 02:00 local time.  The affected
2547    zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
2548    Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
2549
2550  Changes to past and future time zone abbreviations
2551
2552    The Factory zone now uses the time zone abbreviation -00 instead
2553    of a long English-language string, as -00 is now the normal way to
2554    represent an undefined time zone.
2555
2556    Several zones in Antarctica and the former Soviet Union, along
2557    with zones intended for ships at sea that cannot use POSIX TZ
2558    strings, now use numeric time zone abbreviations instead of
2559    invented or obsolete alphanumeric abbreviations.  The affected
2560    zones are Antarctica/Casey, Antarctica/Davis,
2561    Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
2562    Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
2563    Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
2564    Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
2565    Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
2566    Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
2567    Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
2568    Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
2569    Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
2570    Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
2571    Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
2572    Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
2573    Europe/Minsk, Europe/Samara, Europe/Volgograd, and
2574    Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
2575    was replaced by +05, whereas MSK and MSD were kept as they are not
2576    our invention and are widely used.
2577
2578  Changes to zone names
2579
2580    Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
2581    (Thanks to David Massoud.)
2582
2583  Changes to code
2584
2585    zic no longer generates binary files containing POSIX TZ-like
2586    strings that disagree with the local time type after the last
2587    explicit transition in the data.  This fixes a bug with
2588    Africa/Casablanca and Africa/El_Aaiun in some year-2037 timestamps
2589    on the reference platform.  (Thanks to Alexander Belopolsky for
2590    reporting the bug and suggesting a way forward.)
2591
2592    If the installed localtime and/or posixrules files are symbolic
2593    links, zic now keeps them symbolic links when updating them, for
2594    compatibility with platforms like OpenSUSE where other programs
2595    configure these files as symlinks.
2596
2597    zic now avoids hard linking to symbolic links, avoids some
2598    unnecessary mkdir and stat system calls, and uses shorter file
2599    names internally.
2600
2601    zdump has a new -i option to generate transitions in a
2602    smaller but still human-readable format.  This option is
2603    experimental, and the output format may change in future versions.
2604    (Thanks to Jon Skeet for suggesting that an option was needed,
2605    and thanks to Tim Parenti and Chris Rovick for further comments.)
2606
2607  Changes to build procedure
2608
2609    An experimental distribution format is available, in addition
2610    to the traditional format which will continue to be distributed.
2611    The new format is a tarball tzdb-VERSION.tar.lz with signature
2612    file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
2613    tzdb-VERSION containing the code and data of the traditional
2614    two-tarball format, along with extra data that may be useful.
2615    (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
2616    for comments about the experimental format.)
2617
2618    The release version number is now more accurate in the usual case
2619    where releases are built from a Git repository.  For example, if
2620    23 commits and some working-file changes have been made since
2621    release 2016g, the version number is now something like
2622    '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
2623    Tagged releases use the same version number format as before,
2624    e.g., '2016g'.  To support the more accurate version number, its
2625    specification has moved from a line in the Makefile to a new
2626    source file 'version'.
2627
2628    The experimental distribution contains a file to2050.tzs that
2629    contains what should be the output of 'zdump -i -c 2050' on
2630    primary zones.  If this file is available, 'make check' now checks
2631    that zdump generates this output.
2632
2633    'make check_web' now works on Fedora-like distributions.
2634
2635  Changes to documentation and commentary
2636
2637    tzfile.5 now documents the new restriction on POSIX TZ-like
2638    strings that is now implemented by zic.
2639
2640    Comments now cite URLs for some 1917-1921 Russian DST decrees.
2641    (Thanks to Alexander Belopolsky.)
2642
2643    tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
2644    (thanks to Meno Hochschild) and ThreeTen-Extra, and its
2645    description of Java 8 has been brought up to date (thanks to
2646    Stephen Colebourne).  Its description of local time on Mars has
2647    been updated to match current practice, and URLs have been updated
2648    and some obsolete ones removed.
2649
2650
2651Release 2016f - 2016-07-05 16:26:51 +0200
2652
2653  Changes affecting future timestamps
2654
2655    The Egyptian government changed its mind on short notice, and
2656    Africa/Cairo will not introduce DST starting 2016-07-07 after all.
2657    (Thanks to Mina Samuel.)
2658
2659    Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
2660    (Thanks to Stepan Golosunov.)
2661
2662  Changes to past and future timestamps
2663
2664    Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
2665    abbreviations instead of invented ones.
2666
2667  Changes affecting past timestamps
2668
2669    Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
2670    (Thanks to Stepan Golosunov.)
2671
2672
2673Release 2016e - 2016-06-14 08:46:16 -0700
2674
2675  Changes affecting future timestamps
2676
2677    Africa/Cairo observes DST in 2016 from July 7 to the end of October.
2678    Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
2679    For future years, guess April's last Thursday to October's last
2680    Thursday except for Ramadan.
2681
2682  Changes affecting past timestamps
2683
2684    Locations while uninhabited now use '-00', not 'zzz', as a
2685    placeholder time zone abbreviation.  This is inspired by Internet
2686    RFC 3339 and is more consistent with numeric time zone
2687    abbreviations already used elsewhere.  The change affects several
2688    arctic and antarctic locations, e.g., America/Cambridge_Bay before
2689    1920 and Antarctica/Troll before 2005.
2690
2691    Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
2692    at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
2693
2694  Changes to code
2695
2696    zic now outputs a dummy transition at time 2**31 - 1 in zones
2697    whose POSIX-style TZ strings contain a '<'.  This mostly works
2698    around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
2699    (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
2700
2701  Changes affecting documentation and commentary
2702
2703    tz-link.htm says why governments should give plenty of notice for
2704    time zone or DST changes, and refers to Matt Johnson's blog post.
2705
2706    tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
2707
2708
2709Release 2016d - 2016-04-17 22:50:29 -0700
2710
2711  Changes affecting future timestamps
2712
2713    America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
2714    (Thanks to Alexander Krivenyshev for the heads-up.)
2715
2716    Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
2717    (Thanks to Alexander Krivenyshev and Matt Johnson.)
2718
2719    New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
2720    Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
2721    at 02:00.  (Thanks to Stepan Golosunov.)
2722
2723  Changes affecting past timestamps
2724
2725    New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
2726    Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
2727    1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
2728    the same change.  (Thanks to Stepan Golosunov.)
2729
2730    Russia and nearby locations had daylight-saving transitions on
2731    1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
2732    1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
2733    Golosunov.)
2734
2735    Many corrections to historical time in Kazakhstan from 1991
2736    through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
2737    invented time zone abbreviations with numeric abbreviations.
2738
2739  Changes to commentary
2740
2741    Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
2742
2743
2744Release 2016c - 2016-03-23 00:51:27 -0700
2745
2746  Changes affecting future timestamps
2747
2748    Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
2749
2750    Chile reverts from permanent to seasonal DST.  (Thanks to Juan
2751    Correa for the heads-up, and to Tim Parenti for corrections.)
2752    Guess that future transitions are August's and May's second
2753    Saturdays at 24:00 mainland time.  Also, call the period from
2754    2014-09-07 through 2016-05-14 daylight saving time instead of
2755    standard time, as that seems more appropriate now.
2756
2757  Changes affecting past timestamps
2758
2759    Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
2760    +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
2761    from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
2762    (Thanks to Stepan Golosunov.)
2763
2764  Changes to commentary
2765
2766    Several updates and URLs for historical and proposed Russian changes.
2767    (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
2768
2769
2770Release 2016b - 2016-03-12 17:30:14 -0800
2771
2772  Compatibility note
2773
2774    Starting with release 2016b, some data entries cause zic implementations
2775    derived from tz releases 2005j through 2015e to issue warnings like
2776    "time zone abbreviation differs from POSIX standard (+03)".
2777    These warnings should not otherwise affect zic's output and can safely be
2778    ignored on today's platforms, as the warnings refer to a restriction in
2779    POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
2780    warnings is to upgrade to zic derived from tz releases 2015f and later.
2781
2782  Changes affecting future timestamps
2783
2784    New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
2785    Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
2786    2016-03-27 at 02:00 local time.  They need distinct zones since their
2787    post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
2788    Altai Republic, Russia, which will switch from +06 to +07 on the same date
2789    and local time.  The Astrakhan change is already official; the others have
2790    passed the first reading in the State Duma and are extremely likely.
2791    Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
2792    (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
2793    and Stepan Golosunov for followup.)
2794
2795    As a trial of a new system that needs less information to be made up,
2796    the new zones use numeric time zone abbreviations like "+04"
2797    instead of invented abbreviations like "ASTT".
2798
2799    Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
2800    Steffen Thorsen.)
2801
2802    Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
2803    (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
2804    Saturday at 01:00, not March's last Friday at 24:00.
2805
2806  Changes affecting past timestamps
2807
2808    Europe/Chisinau observed DST during 1990, and switched from +04 to
2809    +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
2810    (Thanks to Stepan Golosunov.)
2811
2812    1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
2813    KUYT/KUYST.  (Thanks to Stepan Golosunov.)
2814
2815  Changes to code
2816
2817    tzselect's diagnostics and checking, and checktab.awk's checking,
2818    have been improved.  (Thanks to J William Piggott.)
2819
2820    tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
2821
2822    tzselect now tests Julian-date TZ settings more accurately.
2823    (Thanks to J William Piggott.)
2824
2825  Changes to commentary
2826
2827    Comments in zone tables have been improved.  (Thanks to J William Piggott.)
2828
2829    tzselect again limits its menu comments so that menus fit on a
2830    24×80 alphanumeric display.
2831
2832    A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
2833
2834    In the Theory file, the description of possible time zone abbreviations in
2835    tzdata has been cleaned up, as the old description was unclear and
2836    inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
2837
2838
2839Release 2016a - 2016-01-26 23:28:02 -0800
2840
2841  Changes affecting future timestamps
2842
2843    America/Cayman will not observe daylight saving this year after all.
2844    Revert our guess that it would.  (Thanks to Matt Johnson.)
2845
2846    Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
2847    (Thanks to Alexander Krivenyshev.)
2848
2849    Asia/Tehran now has DST predictions for the year 2038 and later,
2850    to be March 21 00:00 to September 21 00:00.  This is likely better
2851    than predicting no DST, albeit off by a day every now and then.
2852
2853  Changes affecting past and future timestamps
2854
2855    America/Metlakatla switched from PST all year to AKST/AKDT on
2856    2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
2857
2858    America/Santa_Isabel has been removed, and replaced with a
2859    backward compatibility link to America/Tijuana.  Its contents were
2860    apparently based on a misreading of Mexican legislation.
2861
2862  Changes affecting past timestamps
2863
2864    Asia/Karachi's two transition times in 2002 were off by a minute.
2865    (Thanks to Matt Johnson.)
2866
2867  Changes affecting build procedure
2868
2869    An installer can now combine leap seconds with use of the backzone file,
2870    e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
2871    The old 'make posix_packrat' rule is now marked as obsolescent.
2872    (Thanks to Ian Abbott for an initial implementation.)
2873
2874  Changes affecting documentation and commentary
2875
2876    A new file LICENSE makes it easier to see that the code and data
2877    are mostly public-domain.  (Thanks to James Knight.)  The three
2878    non-public-domain files now use the current (3-clause) BSD license
2879    instead of older versions of that license.
2880
2881    tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
2882    CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
2883    on editing tz source files (with a mention of Sublime zoneinfo,
2884    thanks to Gilmore Davidson).
2885
2886    The Theory and asia files now mention the 2015 book "The Global
2887    Transformation of Time, 1870-1950", and cite a couple of reviews.
2888
2889    The America/Chicago entry now documents the informal use of US
2890    central time in Fort Pierre, South Dakota.  (Thanks to Rick
2891    McDermid, Matt Johnson, and Steve Jones.)
2892
2893
2894Release 2015g - 2015-10-01 00:39:51 -0700
2895
2896  Changes affecting future timestamps
2897
2898    Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
2899    (Thanks to Fatih.)
2900
2901    Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
2902    (Thanks to Alexander Krivenyshev.)
2903
2904    Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
2905    (Thanks to Ken Rylander.)
2906
2907    Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
2908    effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
2909    New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
2910
2911  Changes affecting past timestamps
2912
2913    Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
2914
2915  Changes affecting code
2916
2917    localtime no longer mishandles America/Anchorage after 2037.
2918    (Thanks to Bradley White for reporting the bug.)
2919
2920    On hosts with signed 32-bit time_t, localtime no longer mishandles
2921    Pacific/Fiji after 2038-01-16 14:00 UTC.
2922
2923    The localtime module allows the variables 'timezone', 'daylight',
2924    and 'altzone' to be in common storage shared with other modules,
2925    and declares them in case the system <time.h> does not.
2926    (Problems reported by Kees Dekker.)
2927
2928    On platforms with tm_zone, strftime.c now assumes it is not NULL.
2929    This simplifies the code and is consistent with zdump.c.
2930    (Problem reported by Christos Zoulas.)
2931
2932  Changes affecting documentation
2933
2934   The tzfile man page now documents that transition times denote the
2935   starts (not the ends) of the corresponding time periods.
2936   (Ambiguity reported by Bill Seymour.)
2937
2938
2939Release 2015f - 2015-08-10 18:06:56 -0700
2940
2941  Changes affecting future timestamps
2942
2943    North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
2944    The abbreviation remains "KST".  (Thanks to Robert Elz.)
2945
2946    Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
2947    and Pablo Camargo.)
2948
2949  Changes affecting past and future timestamps
2950
2951    Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
2952    (Thanks to Roman Tudos.)
2953
2954  Changes affecting data format and code
2955
2956    zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
2957    field of a Rule line should now be '-'; the old values 'even',
2958    'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
2959    Although the implementation has not changed, these features do not
2960    work in the default installation, they are not used in the data,
2961    and they are now considered obsolescent.
2962
2963    zic now checks that two rules don't take effect at the same time.
2964    (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
2965    simultaneity are now documented.
2966
2967    The two characters '%z' in a zone format now stand for the UT
2968    offset, e.g., '-07' for seven hours behind UT and '+0530' for
2969    five hours and thirty minutes ahead.  This better supports time
2970    zone abbreviations conforming to POSIX.1-2001 and later.
2971
2972  Changes affecting installed data files
2973
2974    Comments for America/Halifax and America/Glace_Bay have been improved.
2975    (Thanks to Brian Inglis.)
2976
2977    Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
2978    Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
2979    installed data files for Europe/Simferopol and Europe/Tallinn.
2980    It does not affect timestamps.  (Thanks to Howard Hinnant.)
2981
2982  Changes affecting code
2983
2984    zdump and zic no longer warn about valid time zone abbreviations
2985    like '-05'.
2986
2987    Some Visual Studio 2013 warnings have been suppressed.
2988    (Thanks to Kees Dekker.)
2989
2990    'date' no longer sets the time of day and its -a, -d, -n and -t
2991    options have been removed.  Long obsolescent, the implementation
2992    of these features had porting problems.  Builders no longer need
2993    to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
2994    (Thanks to Kees Dekker for pointing out the problem.)
2995
2996  Changes affecting documentation
2997
2998    The Theory file mentions naming issues earlier, as these seem to be
2999    poorly publicized (thanks to Gilmore Davidson for reporting the problem).
3000
3001    tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
3002
3003    Mention that Herbert Samuel introduced the term "Summer Time".
3004
3005
3006Release 2015e - 2015-06-13 10:56:02 -0700
3007
3008  Changes affecting future timestamps
3009
3010    Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
3011    not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
3012
3013    Assume Cayman Islands will observe DST starting next year, using US rules.
3014    Although it isn't guaranteed, it is the most likely.
3015
3016  Changes affecting data format
3017
3018    The file 'iso3166.tab' now uses UTF-8, so that its entries can better
3019    spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
3020
3021  Changes affecting code
3022
3023    When displaying data, tzselect converts it to the current locale's
3024    encoding if the iconv command works.  (Problem reported by random832.)
3025
3026    tzselect no longer mishandles Dominica, fixing a bug introduced
3027    in Release 2014f.  (Problem reported by Owen Leibman.)
3028
3029    zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
3030    This fixes a bug introduced in Release 2014f.
3031    (Problem reported by Leonardo Chiquitto.)
3032
3033
3034Release 2015d - 2015-04-24 08:09:46 -0700
3035
3036  Changes affecting future timestamps
3037
3038    Egypt will not observe DST in 2015 and will consider canceling it
3039    permanently.  For now, assume no DST indefinitely.
3040    (Thanks to Ahmed Nazmy and Tim Parenti.)
3041
3042  Changes affecting past timestamps
3043
3044    America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
3045    1966-07-01.  Also, Yukon's time zone history is documented better.
3046    (Thanks to Brian Inglis and Dennis Ferguson.)
3047
3048  Change affecting past and future time zone abbreviations
3049
3050    The abbreviations for Hawaii-Aleutian standard and daylight times
3051    have been changed from HAST/HADT to HST/HDT, as per US Government
3052    Printing Office style.  This affects only America/Adak since 1983,
3053    as America/Honolulu was already using the new style.
3054
3055  Changes affecting code
3056
3057   zic has some minor performance improvements.
3058
3059
3060Release 2015c - 2015-04-11 08:55:55 -0700
3061
3062  Changes affecting future timestamps
3063
3064    Egypt's spring-forward transition is at 24:00 on April's last Thursday,
3065    not 00:00 on April's last Friday.  2015's transition will therefore be on
3066    Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
3067    apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
3068
3069  Changes affecting past timestamps
3070
3071    The following changes affect some pre-1991 Chile-related timestamps
3072    in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
3073
3074      The 1910 transition was January 10, not January 1.
3075
3076      The 1918 transition was September 10, not September 1.
3077
3078      The UT -04 time observed from 1932 to 1942 is now considered to
3079      be standard time, not year-round DST.
3080
3081      Santiago observed DST (UT -03) from 1946-07-15 through
3082      1946-08-31, then reverted to standard time, then switched to -05
3083      on 1947-04-01.
3084
3085      Assume transitions before 1968 were at 00:00, since we have no data
3086      saying otherwise.
3087
3088      The spring 1988 transition was 1988-10-09, not 1988-10-02.
3089      The fall 1990 transition was 1990-03-11, not 1990-03-18.
3090
3091      Assume no UT offset change for Pacific/Easter on 1890-01-01,
3092      and omit all transitions on Pacific/Easter from 1942 through 1946
3093      since we have no data suggesting that they existed.
3094
3095    One more zone has been turned into a link, as it differed
3096    from an existing zone only for older timestamps.  As usual,
3097    this change affects UT offsets in pre-1970 timestamps only.
3098    The zone's old contents have been moved to the 'backzone' file.
3099    The affected zone is America/Montreal.
3100
3101  Changes affecting commentary
3102
3103    Mention the TZUpdater tool.
3104
3105    Mention "The Time Now".  (Thanks to Brandon Ramsey.)
3106
3107
3108Release 2015b - 2015-03-19 23:28:11 -0700
3109
3110  Changes affecting future timestamps
3111
3112    Mongolia will start observing DST again this year, from the last
3113    Saturday in March at 02:00 to the last Saturday in September at 00:00.
3114    (Thanks to Ganbold Tsagaankhuu.)
3115
3116    Palestine will start DST on March 28, not March 27.  Also,
3117    correct the fall 2014 transition from September 26 to October 24.
3118    Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
3119
3120  Changes affecting past timestamps
3121
3122    The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
3123    regression.  (Thanks to Stuart Bishop for reporting the problem.)
3124
3125    Some more zones have been turned into links, when they differed
3126    from existing zones only for older timestamps.  As usual,
3127    these changes affect UT offsets in pre-1970 timestamps only.
3128    Their old contents have been moved to the 'backzone' file.
3129    The affected zones are: America/Antigua, America/Cayman,
3130    Pacific/Midway, and Pacific/Saipan.
3131
3132  Changes affecting time zone abbreviations
3133
3134    Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
3135    (Thanks to Hank W.)
3136
3137  Changes affecting code
3138
3139    Fix integer overflow bug in reference 'mktime' implementation.
3140    (Problem reported by Jörg Richter.)
3141
3142    Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
3143    to be used in the same executable as standard-library time_t functions.
3144    (Problems reported by Bradley White.)
3145
3146  Changes affecting commentary
3147
3148    Cite the recent Mexican decree changing Quintana Roo's time zone.
3149    (Thanks to Carlos Raúl Perasso.)
3150
3151    Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
3152
3153    Update info about Mars time.
3154
3155
3156Release 2015a - 2015-01-29 22:35:20 -0800
3157
3158  Changes affecting future timestamps
3159
3160    The Mexican state of Quintana Roo, represented by America/Cancun,
3161    will shift from Central Time with DST to Eastern Time without DST
3162    on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
3163
3164    Chile will not change clocks in April or thereafter; its new standard time
3165    will be its old daylight saving time.  This affects America/Santiago,
3166    Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
3167
3168    New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
3169    (Thanks to Tim Parenti.)
3170
3171  Changes affecting past timestamps
3172
3173    Iceland observed DST in 1919 and 1921, and its 1939 fallback
3174    transition was Oct. 29, not Nov. 29.  Remove incorrect data from
3175    Shanks about time in Iceland between 1837 and 1908.
3176
3177    Some more zones have been turned into links, when they differed
3178    from existing zones only for older timestamps.  As usual,
3179    these changes affect UT offsets in pre-1970 timestamps only.
3180    Their old contents have been moved to the 'backzone' file.
3181    The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
3182    and Asia/Muscat.
3183
3184  Changes affecting code
3185
3186    tzalloc now scrubs time zone abbreviations compatibly with the way
3187    that tzset always has, by replacing invalid bytes with '_' and by
3188    shortening too-long abbreviations.
3189
3190    tzselect ports to POSIX awk implementations, no longer mishandles
3191    POSIX TZ settings when GNU awk is used, and reports POSIX TZ
3192    settings to the user.  (Thanks to Stefan Kuhn.)
3193
3194  Changes affecting build procedure
3195
3196    'make check' now checks for links to links in the data.
3197    One such link (for Africa/Asmera) has been fixed.
3198    (Thanks to Stephen Colebourne for pointing out the problem.)
3199
3200  Changes affecting commentary
3201
3202    The leapseconds file commentary now mentions the expiration date.
3203    (Problem reported by Martin Burnicki.)
3204
3205    Update Mexican Library of Congress URL.
3206
3207
3208Release 2014j - 2014-11-10 17:37:11 -0800
3209
3210  Changes affecting current and future timestamps
3211
3212    Turks & Caicos' switch from US eastern time to UT -04 year-round
3213    did not occur on 2014-11-02 at 02:00.  It's currently scheduled
3214    for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
3215
3216  Changes affecting past timestamps
3217
3218    Many pre-1989 timestamps have been corrected for Asia/Seoul and
3219    Asia/Pyongyang, based on sources for the Korean-language Wikipedia
3220    entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
3221    longer guess that Pyongyang mimicked Seoul time after World War II,
3222    as this is politically implausible.
3223
3224    Some more zones have been turned into links, when they differed
3225    from existing zones only for older timestamps.  As usual,
3226    these changes affect UT offsets in pre-1970 timestamps only.
3227    Their old contents have been moved to the 'backzone' file.
3228    The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
3229    Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
3230    Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
3231    Indian/Mayotte.
3232
3233  Changes affecting commentary
3234
3235    The commentary is less enthusiastic about Shanks as a source,
3236    and is more careful to distinguish UT from UTC.
3237
3238
3239Release 2014i - 2014-10-21 22:04:57 -0700
3240
3241  Changes affecting future timestamps
3242
3243    Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
3244    (Thanks to Ken Rylander for the heads-up.)  Guess that future
3245    years will use a similar pattern.
3246
3247    A new Zone Pacific/Bougainville, for the part of Papua New Guinea
3248    that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
3249    (Thanks to Kiley Walbom for the heads-up.)
3250
3251  Changes affecting time zone abbreviations
3252
3253    Since Belarus is not changing its clocks even though Moscow is,
3254    the time zone abbreviation in Europe/Minsk is changing from FET
3255    to its more traditional value MSK on 2014-10-26 at 01:00.
3256    (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
3257
3258    The new abbreviation IDT stands for the pre-1976 use of UT +08 in
3259    Indochina, to distinguish it better from ICT (+07).
3260
3261  Changes affecting past timestamps
3262
3263    Many timestamps have been corrected for Asia/Ho_Chi_Minh before 1976
3264    (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
3265    authoritative book).  Asia/Ho_Chi_Minh has been added to
3266    zone1970.tab, to give tzselect users in Vietnam two choices,
3267    since north and south Vietnam disagreed after our 1970 cutoff.
3268
3269    Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
3270    they differed from existing zones only for older timestamps.  As
3271    usual, these changes affect pre-1970 timestamps only.  Their old
3272    contents have been moved to the 'backzone' file.
3273
3274  Changes affecting code
3275
3276    The time-related library functions now set errno on failure, and
3277    some crashes in the new tzalloc-related library functions have
3278    been fixed.  (Thanks to Christos Zoulas for reporting most of
3279    these problems and for suggesting fixes.)
3280
3281    If USG_COMPAT is defined and the requested timestamp is standard time,
3282    the tz library's localtime and mktime functions now set the extern
3283    variable timezone to a value appropriate for that timestamp; and
3284    similarly for ALTZONE, daylight saving time, and the altzone variable.
3285    This change is a companion to the tzname change in 2014h, and is
3286    designed to make timezone and altzone more compatible with tzname.
3287
3288    The tz library's functions now set errno to EOVERFLOW if they fail
3289    because the result cannot be represented.  ctime and ctime_r now
3290    return NULL and set errno when a timestamp is out of range, rather
3291    than having undefined behavior.
3292
3293    Some bugs associated with the new 2014g functions have been fixed.
3294    This includes a bug that largely incapacitated the new functions
3295    time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
3296    It also includes some uses of uninitialized variables after tzalloc.
3297    The new code uses the standard type 'ssize_t', which the Makefile
3298    now gives porting advice about.
3299
3300  Changes affecting commentary
3301
3302    Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
3303
3304
3305Release 2014h - 2014-09-25 18:59:03 -0700
3306
3307  Changes affecting past timestamps
3308
3309    America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
3310
3311    Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
3312    not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
3313
3314    Some more zones have been turned into links, when they differed
3315    from existing zones only for older timestamps.  As usual,
3316    these changes affect UT offsets in pre-1970 timestamps only.
3317    Their old contents have been moved to the 'backzone' file.
3318    The affected zones are: Africa/Blantyre, Africa/Bujumbura,
3319    Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
3320    Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
3321
3322  Changes affecting code
3323
3324    zdump -V and -v now output gmtoff= values on all platforms,
3325    not merely on platforms defining TM_GMTOFF.
3326
3327    The tz library's localtime and mktime functions now set tzname to a value
3328    appropriate for the requested timestamp, and zdump now uses this
3329    on platforms not defining TM_ZONE, fixing a 2014g regression.
3330    (Thanks to Tim Parenti for reporting the problem.)
3331
3332    The tz library no longer sets tzname if localtime or mktime fails.
3333
3334    zdump -c no longer mishandles transitions near year boundaries.
3335    (Thanks to Tim Parenti for reporting the problem.)
3336
3337    An access to uninitialized data has been fixed.
3338    (Thanks to Jörg Richter for reporting the problem.)
3339
3340    When THREAD_SAFE is defined, the code ports to the C11 memory model.
3341    A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
3342    and two threads race to initialize data used by gmtime-like functions.
3343    (Thanks to Andy Heninger for reporting the problems.)
3344
3345  Changes affecting build procedure
3346
3347    'make check' now checks better for properly sorted data.
3348
3349  Changes affecting documentation and commentary
3350
3351    zdump's gmtoff=N output is now documented, and its isdst=D output
3352    is now documented to possibly output D values other than 0 or 1.
3353
3354    zdump -c's treatment of years is now documented to use the
3355    Gregorian calendar and Universal Time without leap seconds,
3356    and its behavior at cutoff boundaries is now documented better.
3357    (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
3358
3359    Programs are now documented to use the proleptic Gregorian calendar.
3360    (Thanks to Alan Barrett for the suggestion.)
3361
3362    Fractional-second GMT offsets have been documented for civil time
3363    in 19th-century Chennai, Jakarta, and New York.
3364
3365
3366Release 2014g - 2014-08-28 12:31:23 -0700
3367
3368  Changes affecting future timestamps
3369
3370    Turks & Caicos is switching from US eastern time to UT -04
3371    year-round, modeled as a switch on 2014-11-02 at 02:00.
3372    [As noted in 2014j, this switch was later delayed.]
3373
3374  Changes affecting past timestamps
3375
3376    Time in Russia or the USSR before 1926 or so has been corrected by
3377    a few seconds in the following zones: Asia/Irkutsk,
3378    Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
3379    Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
3380    Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
3381    Vladimir Karpinsky.)
3382
3383    The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
3384    This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
3385    Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
3386    GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
3387    (Thanks to Stephen Colebourne for pointing to the decree.)
3388
3389    Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
3390
3391    A new file 'backzone' contains data which may appeal to
3392    connoisseurs of old timestamps, although it is out of scope for
3393    the tz database, is often poorly sourced, and contains some data
3394    that is known to be incorrect.  The new file is not recommended
3395    for ordinary use and its entries are not installed by default.
3396    (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
3397    Isle of Man entries.)
3398
3399    Some more zones have been turned into links, when they differed
3400    from existing zones only for older timestamps.  As usual,
3401    these changes affect UT offsets in pre-1970 timestamps only.
3402    Their old contents have been moved to the 'backzone' file.
3403    The affected zones are: Africa/Bangui, Africa/Brazzaville,
3404    Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
3405    Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
3406
3407  Changes affecting code
3408
3409    Unless NETBSD_INSPIRED is defined to 0, the tz library now
3410    supplies functions for creating and using objects that represent
3411    timezones. The new functions are tzalloc, tzfree, localtime_rz,
3412    mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
3413    time2posix_z.  They are intended for performance: for example,
3414    localtime_rz (unlike localtime_r) is trivially thread-safe without
3415    locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
3416    functions, and to Alan Barrett and Jonathan Lennox for helping to
3417    debug the change.)
3418
3419    zdump now builds with the tz library unless USE_LTZ is defined to 0,
3420    This lets zdump use tz features even if the system library lacks them.
3421    To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
3422    TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
3423
3424    zdump now uses localtime_rz if available, as it's significantly faster,
3425    and it can help zdump better diagnose invalid timezone names.
3426    Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
3427    defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
3428    not available, zdump now uses localtime_r and tzset if available,
3429    as this is a bit cleaner and faster than plain localtime.  Compile
3430    with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
3431    lacks these two functions.
3432
3433    If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
3434    Although not needed for tz's own applications, which are single-threaded,
3435    this supports POSIX better if the tz library is used in multithreaded apps.
3436
3437    Some crashes have been fixed when zdump or the tz library is given
3438    invalid or outlandish input.
3439
3440    The tz library no longer mishandles leap seconds on platforms with
3441    unsigned time_t in timezones that lack ordinary transitions after 1970.
3442
3443    The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
3444    already defined, to make it easier to configure on common platforms.
3445    Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
3446
3447    Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
3448    assumes that reading uninitialized memory yields garbage values
3449    but does not cause other problems such as traps.
3450
3451    If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
3452    more likely to guess right for ambiguous timestamps near
3453    transitions where tm_isdst does not change.
3454
3455    If HAVE_STRFTIME_L is defined to 1, the tz library now defines
3456    strftime_l for compatibility with recent versions of POSIX.
3457    Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
3458    to 1 on recent POSIX versions, and to 0 otherwise.
3459
3460    tzselect -c now uses a hybrid distance measure that works better
3461    in Africa.  (Thanks to Alan Barrett for noting the problem.)
3462
3463    The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
3464    or when time_tz is defined.
3465
3466    When HAVE_UTMPX_H is set the 'date' command now builds on systems
3467    whose <utmpx.h> file does not define WTMPX_FILE, and when setting
3468    the date it updates the wtmpx file if _PATH_WTMPX is defined.
3469    This affects GNU/Linux and similar systems.
3470
3471    For easier maintenance later, some C code has been simplified,
3472    some lint has been removed, and the code has been tweaked so that
3473    plain 'make' is more likely to work.
3474
3475    The C type 'bool' is now used for boolean values, instead of 'int'.
3476
3477    The long-obsolete LOCALE_HOME code has been removed.
3478
3479    The long-obsolete 'gtime' function has been removed.
3480
3481  Changes affecting build procedure
3482
3483    'zdump' no longer links in ialloc.o, as it's not needed.
3484
3485    'make check_time_t_alternatives' no longer assumes GNU diff.
3486
3487  Changes affecting distribution tarballs
3488
3489    The files checktab.awk and zoneinfo2tdf.pl are now distributed in
3490    the tzdata tarball instead of the tzcode tarball, since they help
3491    maintain the data.  The NEWS and Theory files are now also
3492    distributed in the tzdata tarball, as they're relevant for data.
3493    (Thanks to Alan Barrett for pointing this out.)  Also, the
3494    leapseconds.awk file is no longer distributed in the tzcode
3495    tarball, since it belongs in the tzdata tarball (where 2014f
3496    inadvertently also distributed it).
3497
3498  Changes affecting documentation and commentary
3499
3500    A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
3501    suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
3502    for debugging it.)
3503
3504    The man pages have been updated to use function prototypes,
3505    to document thread-safe variants like localtime_r, and to document
3506    the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
3507    mktime_z.
3508
3509    The fields in Link lines have been renamed to be more descriptive
3510    and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
3511    and LINK-TO has become LINK-NAME.
3512
3513    tz-link.htm mentions the IETF's tzdist working group; Windows
3514    Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
3515
3516    Some broken URLs have been fixed in the commentary.  (Thanks to
3517    Lester Caine.)
3518
3519    Commentary about Philippines DST has been updated, and commentary
3520    on pre-1970 time in India has been added.
3521
3522
3523Release 2014f - 2014-08-05 17:42:36 -0700
3524
3525  Changes affecting future timestamps
3526
3527    Russia will subtract an hour from most of its time zones on 2014-10-26
3528    at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
3529    There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
3530    Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
3531    (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
3532    (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
3533    (Europe/Samara) are not changing their clocks.  The changed zones are
3534    Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
3535    Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
3536    Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
3537    Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
3538    subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
3539    but not its UTC offset.  Two zones are added: Asia/Chita (split
3540    from Asia/Yakutsk, and also with two hours subtracted) and
3541    Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
3542    subtracted).  (Thanks to Tim Parenti for much of the above.)
3543
3544  Changes affecting time zone abbreviations
3545
3546    Australian eastern time zone abbreviations are now AEST/AEDT not EST,
3547    and similarly for the other Australian zones.  That is, for eastern
3548    standard and daylight saving time the abbreviations are AEST and AEDT
3549    instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
3550    and AWST/AWDT are now used instead of the former CST, CWST, and WST.
3551    This change does not affect UT offsets, only time zone abbreviations.
3552    (Thanks to Rich Tibbett and many others.)
3553
3554    Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
3555    effective 2014-10-26 at 02:00 local time.
3556
3557    The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
3558    has been changed from URUT to XJT.  (Thanks to Luther Ma.)
3559
3560    Prefer MSK/MSD for Moscow time in Russia, even in other cities.
3561    Similarly, prefer EET/EEST for eastern European time in Russia.
3562
3563    Change time zone abbreviations in (western) Samoa to use "ST" and
3564    "DT" suffixes, as this is more likely to match common practice.
3565    Prefix "W" to (western) Samoa time when its standard-time offset
3566    disagrees with that of American Samoa.
3567
3568    America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
3569
3570    Time zone abbreviations have been updated for Japan's two time
3571    zones used 1896-1937.  JWST now stands for Western Standard
3572    Time, and JCST for Central Standard Time (formerly this was CJT).
3573    These abbreviations are now used for time in Korea, Taiwan,
3574    and Sakhalin while controlled by Japan.
3575
3576  Changes affecting past timestamps
3577
3578    China's five zones have been simplified to two, since the post-1970
3579    differences in the other three seem to have been imaginary.  The
3580    zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
3581    removed; backwards-compatibility links still work, albeit with
3582    different behaviors for timestamps before May 1980.  Asia/Urumqi's
3583    1980 transition to UT +08 has been removed, so that it is now at
3584    +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
3585    Treindl sent helpful translations of two papers by Guo Qingsheng.)
3586
3587    Some zones have been turned into links, when they differed from existing
3588    zones only for older UT offsets where data entries were likely invented.
3589    These changes affect UT offsets in pre-1970 timestamps only.  This is
3590    similar to the change in release 2013e, except this time for western
3591    Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
3592    Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
3593    Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
3594    Atlantic/St_Helena.  This also affects the backwards-compatibility
3595    link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
3596    Tim Parenti, and David Patte for reporting problems in earlier
3597    versions of this change.)
3598
3599    Asia/Shanghai's pre-standard-time UT offset has been changed from
3600    8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
3601    transition to standard time has been changed from 1928 to 1901.
3602
3603    Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
3604    then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
3605    In 1946 it observed DST from 05-15 through 09-30; in 1947
3606    from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
3607    (Thanks to Yu-Cheng Chuang.)
3608
3609    Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
3610
3611    Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
3612    10-03 at 00:00.  (Thanks to Konstantin Hyppönen.)
3613
3614    Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
3615    period from 1911 to 1950.
3616
3617    Pacific/Chatham has been changed to New Zealand standard time plus
3618    45 minutes for the period before 1957, reflecting a 1956 remark in
3619    the New Zealand parliament.
3620
3621    Europe/Budapest has several pre-1946 corrections: in 1918 the transition
3622    out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
3623    1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
3624    not 04-06 at 02:00; and there was no DST in 1920.
3625
3626    Africa/Accra is now assumed to have observed DST from 1920 through 1935.
3627
3628    Time in Russia before 1927 or so has been corrected by a few seconds in
3629    the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
3630    Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
3631    Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
3632    point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
3633
3634  Changes affecting data format
3635
3636    A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
3637    The new file's extended format allows multiple country codes per zone.
3638    The older file is still installed but is deprecated; its format is
3639    not changing and it will still be distributed for a while, but new
3640    applications should use the new file.
3641
3642    The new file format simplifies maintenance of obscure locations.
3643    To test this, it adds coverage for the Crozet Islands and the
3644    Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
3645
3646    The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
3647    It is still ASCII now, but commentary about the switch has been added.
3648    The new file 'zone1970.tab' already uses UTF-8.
3649
3650  Changes affecting code
3651
3652    'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
3653    is defined.  (Thanks to Elliott Hughes for reporting the problem.)
3654
3655    'zic' no longer mishandles input when ignoring case in locales that
3656    are not compatible with English, e.g., unibyte Turkish locales when
3657    compiled with HAVE_GETTEXT.
3658
3659    Error diagnostics of 'zic' and 'yearistype' have been reworded so that
3660    they no longer use ASCII '-' as if it were a dash.
3661
3662    'zic' now rejects output file names that contain '.' or '..' components.
3663    (Thanks to Tim Parenti for reporting the problem.)
3664
3665    'zic -v' now warns about output file names that do not follow
3666    POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
3667    David Olson for starting the ball rolling on this.)
3668
3669    Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
3670
3671  Changes affecting build procedure
3672
3673    'zic' no longer links in localtime.o and asctime.o, as they're not needed.
3674    (Thanks to John Cochran.)
3675
3676  Changes affecting documentation and commentary
3677
3678    The 'Theory' file documents legacy names, the longstanding
3679    exceptions to the POSIX-inspired file name rules.
3680
3681    The 'zic' documentation clarifies the role of time types when
3682    interpreting dates.  (Thanks to Arthur David Olson.)
3683
3684    Documentation and commentary now prefer UTF-8 to US-ASCII,
3685    allowing the use of proper accents in foreign words and names.
3686    Code and data have not changed because of this.  (Thanks to
3687    Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
3688    this.)
3689
3690    Non-HTML documentation and commentary now use plain-text URLs instead of
3691    HTML insertions, and are more consistent about bracketing URLs when they
3692    are not already surrounded by white space.  (Thanks to suggestions by
3693    Steffen Nurpmeso.)
3694
3695    There is new commentary about Xujiahui Observatory, the five time-zone
3696    project in China from 1918 to 1949, timekeeping in Japanese-occupied
3697    Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
3698    warlord Jin Shuren in the data.
3699
3700    Commentary about the coverage of each Russian zone has been standardized.
3701    (Thanks to Tim Parenti.)
3702
3703    There is new commentary about contemporary timekeeping in Ethiopia.
3704
3705    Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
3706
3707    There is new commentary about time in Poland in 1919.
3708
3709    Proper credit has been given to DST inventor George Vernon Hudson.
3710
3711    Commentary about time in Metlakatla, AK and Resolute, NU has been
3712    improved, with a new source for the former.
3713
3714    In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
3715    is uninhabited.
3716
3717    Commentary about permanent Antarctic bases has been updated.
3718
3719    Several typos have been corrected.  (Thanks to Tim Parenti for
3720    contributing some of these fixes.)
3721
3722    tz-link.htm now mentions the JavaScript libraries Moment Timezone,
3723    TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
3724    from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
3725    (Thanks to a heads-up from Dirkjan Ochtman.)
3726
3727    The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
3728    have been removed.  These obsolescent US Naval Observatory entries were no
3729    longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
3730
3731
3732Release 2014e - 2014-06-12 21:53:52 -0700
3733
3734  Changes affecting near-future timestamps
3735
3736    Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
3737    (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
3738    switch to standard time at 24:00 the last Thursday before Ramadan, and
3739    back to DST at 00:00 the first Friday after Ramadan.
3740
3741    Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
3742    to Milamber Space Network.)  Guess that from 2015 on Morocco will
3743    temporarily switch to standard time at 03:00 the last Saturday before
3744    Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
3745
3746  Changes affecting past timestamps
3747
3748    The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
3749    "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
3750    "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
3751    in 1991.  (Thanks to Hank W. for reporting the problems.)
3752
3753  Changes affecting commentary
3754
3755    tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
3756    draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
3757    removes stale pointers to World Time Explorer and WORLDTIME.
3758
3759
3760Release 2014d - 2014-05-27 21:34:40 -0700
3761
3762  Changes affecting code
3763
3764    zic no longer generates files containing timestamps before the Big Bang.
3765    This works around GNOME glib bug 878
3766    <https://gitlab.gnome.org/GNOME/glib/issues/878>
3767    (Thanks to Leonardo Chiquitto for reporting the bug, and to
3768    Arthur David Olson and James Cloos for suggesting improvements to the fix.)
3769
3770  Changes affecting documentation
3771
3772    tz-link.htm now mentions GNOME.
3773
3774
3775Release 2014c - 2014-05-13 07:44:13 -0700
3776
3777  Changes affecting near-future timestamps
3778
3779    Egypt observes DST starting 2014-05-15 at 24:00.
3780    (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
3781    Details have not been announced, except that DST will not be observed
3782    during Ramadan.  Guess that DST will stop during the same Ramadan dates as
3783    Morocco, and that Egypt's future spring and fall transitions will be the
3784    same as 2010 when it last observed DST, namely April's last Friday at
3785    00:00 to September's last Thursday at 23:00 standard time.  Also, guess
3786    that Ramadan transitions will be at 00:00 standard time.
3787
3788  Changes affecting code
3789
3790    zic now generates transitions for minimum time values, eliminating guesswork
3791    when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
3792
3793    Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
3794
3795  Changes affecting commentary and documentation
3796
3797    Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
3798
3799
3800Release 2014b - 2014-03-24 21:28:50 -0700
3801
3802  Changes affecting near-future timestamps
3803
3804    Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
3805    (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
3806
3807    New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
3808    Bengt-Inge Larsson.)  This is currently an approximation; a better version
3809    will require the zic and localtime fixes mentioned below, and the plan is
3810    to wait for a while until at least the zic fixes propagate.
3811
3812  Changes affecting code
3813
3814    'zic' and 'localtime' no longer reject locations needing four transitions
3815    per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
3816    Also, 'zic' avoids some unlikely failures due to integer overflow.
3817
3818  Changes affecting build procedure
3819
3820    'make check' now detects Rule lines defined but never used.
3821    The NZAQ rules, an instance of this problem, have been removed.
3822
3823  Changes affecting commentary and documentation
3824
3825    Fix Tuesday/Thursday typo in description of time in Israel.
3826    (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
3827
3828    Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
3829    to Donald MacQueen.)  Instead, the Microsoft Windows Store app
3830    library supports them.
3831
3832    Add comments about Johnston Island time in the 1960s.
3833    (Thanks to Lyle McElhaney.)
3834
3835    Morocco's 2014 DST start will be as predicted.
3836    (Thanks to Sebastien Willemijns.)
3837
3838
3839Release 2014a - 2014-03-07 23:30:29 -0800
3840
3841  Changes affecting near-future timestamps
3842
3843    Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
3844    the heads-up, and to Tim Parenti for simplifying the update.)
3845
3846  Changes affecting past timestamps
3847
3848    Fiji ended DST on 2014-01-19 at 02:00, not the previously scheduled 03:00.
3849    (Thanks to Steffen Thorsen.)
3850
3851    Ukraine switched from Moscow to Eastern European time on 1990-07-01
3852    (not 1992-01-01), and observed DST during the entire next winter.
3853    (Thanks to Vladimir in Moscow via Alois Treindl.)
3854
3855    In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
3856    (Thanks to Avigdor Finkelstein.)
3857
3858  Changes affecting code
3859
3860    A uninitialized-storage bug in 'localtime' has been fixed.
3861    (Thanks to Logan Chien.)
3862
3863  Changes affecting the build procedure
3864
3865    The settings for 'make check_web' now default to Ubuntu 13.10.
3866
3867  Changes affecting commentary and documentation
3868
3869    The boundary of the US Pacific time zone is given more accurately.
3870    (Thanks to Alan Mintz.)
3871
3872    Chile's 2014 DST will be as predicted.  (Thanks to José Miguel Garrido.)
3873
3874    Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raúl Perasso.)
3875
3876    Better descriptions of countries with same time zone history as
3877    Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
3878
3879    Several changes affect tz-link.htm, the main web page.
3880
3881      Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
3882      David Braverman).
3883
3884      Mention xCal (Internet RFC 6321) and jCal.
3885
3886      Microsoft has some support for tz database names.
3887
3888      CLDR data formats include both XML and JSON.
3889
3890      Mention Maggiolo's map of solar vs standard time.
3891      (Thanks to Arthur David Olson.)
3892
3893      Mention TZ4Net.  (Thanks to Matt Johnson.)
3894
3895      Mention the timezone-olson Haskell package.
3896
3897      Mention zeitverschiebung.net.  (Thanks to Martin Jäger.)
3898
3899      Remove moribund links to daylight-savings-time.info and to
3900      Simple Timer + Clocks.
3901
3902      Update two links.  (Thanks to Oscar van Vlijmen.)
3903
3904      Fix some formatting glitches, e.g., remove random newlines from
3905      abbr elements' title attributes.
3906
3907
3908Release 2013i - 2013-12-17 07:25:23 -0800
3909
3910  Changes affecting near-future timestamps:
3911
3912    Jordan switches back to standard time at 00:00 on December 20, 2013.
3913    The 2006-2011 transition schedule is planned to resume in 2014.
3914    (Thanks to Steffen Thorsen.)
3915
3916  Changes affecting past timestamps:
3917
3918    In 2004, Cuba began DST on March 28, not April 4.
3919    (Thanks to Steffen Thorsen.)
3920
3921  Changes affecting code
3922
3923    The compile-time flag NOSOLAR has been removed, as nowadays the
3924    benefit of slightly shrinking runtime table size is outweighed by the
3925    cost of disallowing potential future updates that exceed old limits.
3926
3927  Changes affecting documentation and commentary
3928
3929    The files solar87, solar88, and solar89 are no longer distributed.
3930    They were a negative experiment - that is, a demonstration that
3931    tz data can represent solar time only with some difficulty and error.
3932    Their presence in the distribution caused confusion, as Riyadh
3933    civil time was generally not solar time in those years.
3934
3935    tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
3936
3937
3938Release 2013h - 2013-10-25 15:32:32 -0700
3939
3940  Changes affecting current and future timestamps:
3941
3942    Libya has switched its UT offset back to +02 without DST, instead
3943    of +01 with DST.  (Thanks to Even Scharning.)
3944
3945    Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
3946    (Thanks to Gwillim Law.)
3947
3948  Changes affecting future timestamps:
3949
3950    Acre and (we guess) western Amazonas will switch from UT -04 to -05
3951    on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
3952    (Thanks to Steffen Thorsen.)
3953
3954    Add entries for DST transitions in Morocco in the year 2038.
3955    This avoids some year-2038 glitches introduced in 2013g.
3956    (Thanks to Yoshito Umaoka for reporting the problem.)
3957
3958  Changes affecting API
3959
3960    The 'tzselect' command no longer requires the 'select' command,
3961    and should now work with /bin/sh on more platforms.  It also works
3962    around a bug in BusyBox awk before version 1.21.0.  (Thanks to
3963    Patrick 'P. J.' McDermott and Alan Barrett.)
3964
3965  Changes affecting code
3966
3967    Fix localtime overflow bugs with 32-bit unsigned time_t.
3968
3969    zdump no longer assumes sscanf returns maximal values on overflow.
3970
3971  Changes affecting the build procedure
3972
3973    The builder can specify which programs to use, if any, instead of
3974    'ar' and 'ranlib', and libtz.a is now built locally before being
3975    installed.  (Thanks to Michael Forney.)
3976
3977    A dependency typo in the 'zdump' rule has been fixed.
3978    (Thanks to Andrew Paprocki.)
3979
3980    The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
3981    work as specified by POSIX.2-1992 or later; this is portable nowadays.
3982
3983    'make clean' no longer removes 'leapseconds', since it's
3984    host-independent and is part of the distribution.
3985
3986    The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
3987
3988  Changes affecting documentation and commentary
3989
3990    tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
3991    (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
3992
3993    Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
3994    8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
3995    longer maintained) and for old advisories.  SOFA now does C.
3996
3997Release 2013g - 2013-09-30 21:08:26 -0700
3998
3999  Changes affecting current and near-future timestamps
4000
4001    Morocco now observes DST from the last Sunday in March to the last
4002    Sunday in October, not April to September respectively.  (Thanks
4003    to Steffen Thorsen.)
4004
4005  Changes affecting 'zic'
4006
4007    'zic' now runs on platforms that lack both hard links and symlinks.
4008    (Thanks to Theo Veenker for reporting the problem, for MinGW.)
4009    Also, fix some bugs on platforms that lack hard links but have symlinks.
4010
4011    'zic -v' again warns that Asia/Tehran has no POSIX environment variable
4012    to predict the far future, fixing a bug introduced in 2013e.
4013
4014  Changes affecting the build procedure
4015
4016    The 'leapseconds' file is again put into the tzdata tarball.
4017    Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
4018    Matt Burgess and Ian Abbott.)  The timestamps of these and other
4019    dependent files in tarballs are adjusted more consistently.
4020
4021  Changes affecting documentation and commentary
4022
4023    The README file is now part of the data tarball as well as the code.
4024    It now states that files are public domain unless otherwise specified.
4025    (Thanks to Andrew Main (Zefram) for asking for clarifications.)
4026    Its details about the 1989 release moved to a place of honor near
4027    the end of NEWS.
4028
4029
4030Release 2013f - 2013-09-24 23:37:36 -0700
4031
4032  Changes affecting near-future timestamps
4033
4034    Tocantins will very likely not observe DST starting this spring.
4035    (Thanks to Steffen Thorsen.)
4036
4037    Jordan will likely stay at UT +03 indefinitely, and will not fall
4038    back this fall.
4039
4040    Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
4041
4042  Changes affecting API
4043
4044    The types of the global variables 'timezone' and 'altzone' (if present)
4045    have been changed back to 'long'.  This is required for 'timezone'
4046    by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
4047    These variables were originally 'long' in the tz code, but were
4048    mistakenly changed to 'time_t' in 1987; nobody reported the
4049    incompatibility until now.  The difference matters on x32, where
4050    'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
4051
4052  Changes affecting the build procedure
4053
4054    Avoid long strings in leapseconds.awk to work around a mawk bug.
4055    (Thanks to Cyril Baurand.)
4056
4057  Changes affecting documentation and commentary
4058
4059    New file 'NEWS' that contains release notes like this one.
4060
4061    Paraguay's law does not specify DST transition time; 00:00 is customary.
4062    (Thanks to Waldemar Villamayor-Venialbo.)
4063
4064    Minor capitalization fixes.
4065
4066  Changes affecting version-control only
4067
4068    The experimental GitHub repository now contains annotated and
4069    signed tags for recent releases, e.g., '2013e' for Release 2013e.
4070    Releases are tagged starting with 2012e; earlier releases were
4071    done differently, and tags would either not have a simple name or
4072    not exactly match what was released.
4073
4074    'make set-timestamps' is now simpler and a bit more portable.
4075
4076
4077Release 2013e - 2013-09-19 23:50:04 -0700
4078
4079  Changes affecting near-future timestamps
4080
4081    This year Fiji will start DST on October 27, not October 20.
4082    (Thanks to David Wheeler for the heads-up.)  For now, guess that
4083    Fiji will continue to spring forward the Sunday before the fourth
4084    Monday in October.
4085
4086  Changes affecting current and future time zone abbreviations
4087
4088    Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
4089    time zone abbreviations since 1932.  (Thanks to George Ziegler,
4090    Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
4091    Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
4092    Asia/Makassar, and Asia/Pontianak.
4093
4094    Use ART (UT -03, standard time), rather than WARST (also -03, but
4095    daylight saving time) for San Luis, Argentina since 2009.
4096
4097  Changes affecting Godthåb timestamps after 2037 if version mismatch
4098
4099    Allow POSIX-like TZ strings where the transition time's hour can
4100    range from -167 through 167, instead of the POSIX-required 0
4101    through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
4102    new Fiji rules.  This is a more compact way to represent
4103    far-future timestamps for America/Godthab, America/Santiago,
4104    Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
4105    Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
4106    this change.  (Derived from a suggestion by Arthur David Olson.)
4107
4108    Allow POSIX-like TZ strings where daylight saving time is in
4109    effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
4110    Argentina Summer Time all year.  This supports a more compact way
4111    to represent the 2013d data for America/Argentina/San_Luis.
4112    Because of the change for San Luis noted above this change does not
4113    affect the current data.  (Thanks to Andrew Main (Zefram) for
4114    suggestions that improved this change.)
4115
4116    Where these two TZ changes take effect, there is a minor extension
4117    to the tz file format in that it allows new values for the
4118    embedded TZ-format string, and the tz file format version number
4119    has therefore been increased from 2 to 3 as a precaution.
4120    Version-2-based client code should continue to work as before for
4121    all timestamps before 2038.  Existing version-2-based client code
4122    (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
4123    files, and typically works in practice even for timestamps after
4124    2037; the only known exception is America/Godthab.
4125
4126  Changes affecting timestamps before 1970
4127
4128    Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
4129    some errors before 1947.
4130
4131    Some zones have been turned into links, when they differ from existing
4132    zones only in older data entries that were likely invented or that
4133    differ only in LMT or transitions from LMT.  These changes affect
4134    only timestamps before 1943.  The affected zones are:
4135    Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
4136    America/Grenada, America/Guadeloupe, America/Marigot,
4137    America/Montserrat, America/St_Barthelemy, America/St_Kitts,
4138    America/St_Lucia, America/St_Thomas, America/St_Vincent,
4139    America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
4140    confirming that the old Europe/Vaduz zone was wrong and the new
4141    link is better for WWII-era times.)
4142
4143    Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
4144    America/Cayman, America/Jamaica and America/Grand_Turk timestamps
4145    from 1890 to 1912.
4146
4147    Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
4148    This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
4149    to Alois Treindl.)
4150
4151    Change the date of the circa-1850 Zurich transition from 1849-09-12
4152    to 1853-07-16, overriding Shanks with data from Messerli about
4153    postal and telegraph time in Switzerland.
4154
4155  Changes affecting time zone abbreviations before 1970
4156
4157    For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
4158    as Jakarta was called Batavia back then.
4159
4160  Changes affecting API
4161
4162    The 'zic' command now outputs a dummy transition when far-future
4163    data can't be summarized using a TZ string, and uses a 402-year
4164    window rather than a 400-year window.  For the current data, this
4165    affects only the Asia/Tehran file.  It does not affect any of the
4166    timestamps that this file represents, so zdump outputs the same
4167    information as before.  (Thanks to Andrew Main (Zefram).)
4168
4169    The 'date' command has a new '-r' option, which lets you specify
4170    the integer time to display, a la FreeBSD.
4171
4172    The 'tzselect' command has two new options '-c' and '-n', which lets you
4173    select a zone based on latitude and longitude.
4174
4175    The 'zic' command's '-v' option now warns about constructs that
4176    require the new version-3 binary file format.  (Thanks to Arthur
4177    David Olson for the suggestion.)
4178
4179    Support for floating-point time_t has been removed.
4180    It was always dicey, and POSIX no longer requires it.
4181    (Thanks to Eric Blake for suggesting to the POSIX committee to
4182    remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
4183    Heninger, Arthur David Olson, and Alois Treindl, for reporting
4184    bugs and elucidating some of the corners of the old floating-point
4185    implementation.)
4186
4187    The signatures of 'offtime', 'timeoff', and 'gtime' have been
4188    changed back to the old practice of using 'long' to represent UT
4189    offsets.  This had been inadvertently and mistakenly changed to
4190    'int_fast32_t'.  (Thanks to Christos Zoulas.)
4191
4192    The code avoids undefined behavior on integer overflow in some
4193    more places, including gmtime, localtime, mktime and zdump.
4194
4195  Changes affecting the zdump utility
4196
4197    zdump now outputs "UT" when referring to Universal Time, not "UTC".
4198    "UTC" does not make sense for timestamps that predate the introduction
4199    of UTC, whereas "UT", a more generic term, does.  (Thanks to Steve Allen
4200    for clarifying UT vs UTC.)
4201
4202  Data changes affecting behavior of tzselect and similar programs
4203
4204    Country code BQ is now called the more common name "Caribbean Netherlands"
4205    rather than the more official "Bonaire, St Eustatius & Saba".
4206
4207    Remove from zone.tab the names America/Montreal, America/Shiprock,
4208    and Antarctica/South_Pole, as they are equivalent to existing
4209    same-country-code zones for post-1970 timestamps.  The data entries for
4210    these names are unchanged, so the names continue to work as before.
4211
4212  Changes affecting code internals
4213
4214    zic -c now runs way faster on 64-bit hosts when given large numbers.
4215
4216    zic now uses vfprintf to avoid allocating and freeing some memory.
4217
4218    tzselect now computes the list of continents from the data,
4219    rather than have it hard-coded.
4220
4221    Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
4222
4223  Changes affecting the build procedure
4224
4225    The 'leapseconds' file is now generated automatically from a
4226    new file 'leap-seconds.list', which is a copy of
4227    <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
4228    A new source file 'leapseconds.awk' implements this.
4229    The goal is simplification of the future maintenance of 'leapseconds'.
4230
4231    When building the 'posix' or 'right' subdirectories, if the
4232    subdirectory would be a copy of the default subdirectory, it is
4233    now made a symbolic link if that is supported.  This saves about
4234    2 MB of file system space.
4235
4236    The links America/Shiprock and Antarctica/South_Pole have been
4237    moved to the 'backward' file.  This affects only nondefault builds
4238    that omit 'backward'.
4239
4240  Changes affecting version-control only
4241
4242    .gitignore now ignores 'date'.
4243
4244  Changes affecting documentation and commentary
4245
4246    Changes to the 'tzfile' man page
4247
4248      It now mentions that the binary file format may be extended in
4249      future versions by appending data.
4250
4251      It now refers to the 'zdump' and 'zic' man pages.
4252
4253    Changes to the 'zic' man page
4254
4255      It lists conditions that elicit a warning with '-v'.
4256
4257      It says that the behavior is unspecified when duplicate names
4258      are given, or if the source of one link is the target of another.
4259
4260      Its examples are updated to match the latest data.
4261
4262      The definition of white space has been clarified slightly.
4263      (Thanks to Michael Deckers.)
4264
4265    Changes to the 'Theory' file
4266
4267      There is a new section about the accuracy of the tz database,
4268      describing the many ways that errors can creep in, and
4269      explaining why so many of the pre-1970 timestamps are wrong or
4270      misleading (thanks to Steve Allen, Lester Caine, and Garrett
4271      Wollman for discussions that contributed to this).
4272
4273      The 'Theory' file describes LMT better (this follows a
4274      suggestion by Guy Harris).
4275
4276      It refers to the 2013 edition of POSIX rather than the 2004 edition.
4277
4278      It's mentioned that excluding 'backward' should not affect the
4279      other data, and it suggests at least one zone.tab name per
4280      inhabited country (thanks to Stephen Colebourne).
4281
4282      Some longstanding restrictions on names are documented, e.g.,
4283      'America/New_York' precludes 'America/New_York/Bronx'.
4284
4285      It gives more reasons for the 1970 cutoff.
4286
4287      It now mentions which time_t variants are supported, such as
4288      signed integer time_t.  (Thanks to Paul Goyette for reporting
4289      typos in an experimental version of this change.)
4290
4291      (Thanks to Philip Newton for correcting typos in these changes.)
4292
4293    Documentation and commentary is more careful to distinguish UT in
4294    general from UTC in particular.  (Thanks to Steve Allen.)
4295
4296    Add a better source for the Zurich 1894 transition.
4297    (Thanks to Pierre-Yves Berger.)
4298
4299    Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
4300
4301
4302Release 2013d - 2013-07-05 07:38:01 -0700
4303
4304  Changes affecting future timestamps:
4305
4306    Morocco's midsummer transitions this year are July 7 and August 10,
4307    not July 9 and August 8.  (Thanks to Andrew Paprocki.)
4308
4309    Israel now falls back on the last Sunday of October.
4310    (Thanks to Ephraim Silverberg.)
4311
4312  Changes affecting past timestamps:
4313
4314    Specify Jerusalem's location more precisely; this changes the pre-1880
4315    times by 2 s.
4316
4317  Changing affecting metadata only:
4318
4319    Fix typos in the entries for country codes BQ and SX.
4320
4321  Changes affecting code:
4322
4323    Rework the code to fix a bug with handling Australia/Macquarie on
4324    32-bit hosts (thanks to Arthur David Olson).
4325
4326    Port to platforms like NetBSD, where time_t can be wider than long.
4327
4328    Add support for testing time_t types other than the system's.
4329    Run 'make check_time_t_alternatives' to try this out.
4330    Currently, the tests fail for unsigned time_t;
4331    this should get fixed at some point.
4332
4333  Changes affecting documentation and commentary:
4334
4335    Deemphasize the significance of national borders.
4336
4337    Update the zdump man page.
4338
4339    Remove obsolete NOID comment (thanks to Denis Excoffier).
4340
4341    Update several URLs and comments in the web pages.
4342
4343    Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
4344
4345    Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
4346
4347
4348Release 2013c - 2013-04-19 16:17:40 -0700
4349
4350  Changes affecting current and future timestamps:
4351
4352    Palestine observed DST starting March 29, 2013.  (Thanks to
4353    Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
4354    with the predicted rules being the last Thursday in March at 24:00
4355    to the first Friday on or after September 21 at 01:00.
4356
4357    Assume that the recent change to Paraguay's DST rules is permanent,
4358    by moving the end of DST to the 4th Sunday in March every year.
4359    (Thanks to Carlos Raúl Perasso.)
4360
4361  Changes affecting past timestamps:
4362
4363    Fix some historical data for Palestine to agree with that of
4364    timeanddate.com, as follows:
4365
4366	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
4367	  00:00 Apr 1.
4368
4369	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
4370	  02:00.
4371
4372	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
4373
4374	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
4375
4376	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
4377
4378	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
4379
4380    Fix times of habitation for Macquarie to agree with the Tasmania
4381    Parks & Wildlife Service history, which indicates that permanent
4382    habitation was 1899-1919 and 1948 on.
4383
4384  Changing affecting metadata only:
4385
4386    Macquarie Island is politically part of Australia, not Antarctica.
4387    (Thanks to Tobias Conradi.)
4388
4389    Sort Macquarie more consistently with other parts of Australia.
4390    (Thanks to Tim Parenti.)
4391
4392
4393Release 2013b - 2013-03-10 22:33:40 -0700
4394
4395  Changes affecting current and future timestamps:
4396
4397    Haiti uses US daylight-saving rules this year, and presumably future years.
4398    This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
4399
4400    Paraguay will end DST on March 24 this year.
4401    (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
4402
4403    Morocco does not observe DST during Ramadan;
4404    try to predict Ramadan in Morocco as best we can.
4405    (Thanks to Erik Homoet for the heads-up.)
4406
4407  Changes affecting commentary:
4408
4409    Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
4410    Update URL for Solaris.  Mention Internet RFC 6557.
4411    Update Internet RFCs 2445->5545, 2822->5322.
4412    Switch from FTP to HTTP for Internet RFCs.
4413
4414
4415Release 2013a - 2013-02-27 09:20:35 -0800
4416
4417  Change affecting binary data format:
4418
4419    The zone offset at the end of version-2-format zone files is now
4420    allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
4421
4422  Changes affecting current and future timestamps:
4423
4424    Chile's 2013 rules, and we guess rules for 2014 and later, will be
4425    the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
4426    (Thanks to Steffen Thorsen and Robert Elz.)
4427
4428    New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
4429    (Thanks to Tobias Conradi and Arthur David Olson.)
4430
4431  Many changes affect historical timestamps before 1940.
4432  These were deduced from: Milne J. Civil time. Geogr J. 1899
4433  Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
4434
4435  Changes affecting the code:
4436
4437    Fix zic bug that mishandled Egypt's 2010 changes (this also affected
4438    the data).  (Thanks to Arthur David Olson.)
4439
4440    Fix localtime bug when time_t is unsigned and data files were generated
4441    by a signed time_t system.  (Thanks to Doug Bailey for reporting and
4442    to Arthur David Olson for fixing.)
4443
4444    Allow the email address for bug reports to be set by the packager.
4445    The default is tz@iana.org, as before.  (Thanks to Joseph S. Myers.)
4446
4447    Update HTML checking to be compatible with Ubuntu 12.10.
4448
4449    Check that files are a safe subset of ASCII.  At some point we may
4450    relax this requirement to a safe subset of UTF-8.  Without the
4451    check, some non-UTF-8 encodings were leaking into the distribution.
4452
4453  Commentary changes:
4454
4455    Restore a comment about copyright notices that was inadvertently deleted.
4456    (Thanks to Arthur David Olson.)
4457
4458    Improve the commentary about which districts observe what times
4459    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
4460
4461    Add web page links to tz.js.
4462
4463    Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
4464
4465
4466Release 2012j - 2012-11-12 18:34:49 -0800
4467
4468  Libya moved to CET this weekend, but with DST planned next year.
4469  (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
4470
4471  Signatures now have the extension .asc, not .sign, as that's more
4472  standard.  (Thanks to Phil Pennock.)
4473
4474  The output of 'zdump --version', and of 'zic --version', now
4475  uses a format that is more typical for --version.
4476  (Thanks to Joseph S. Myers.)
4477
4478  The output of 'tzselect --help', 'zdump --help', and 'zic --help'
4479  now uses tz@iana.org rather than the old elsie address.
4480
4481  zic -v now complains about abbreviations that are less than 3
4482  or more than 6 characters, as per POSIX.  Formerly, it checked
4483  for abbreviations that were more than 3.
4484
4485  'make public' no longer puts its temporary directory under /tmp,
4486  and uses the just-built zic rather than the system zic.
4487
4488  Various fixes to documentation and commentary.
4489
4490
4491Release 2012i - 2012-11-03 12:57:09 -0700
4492
4493  Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
4494
4495  Linker flags can now be specified via LDFLAGS.
4496  AWK now defaults to 'awk', not 'nawk'.
4497  The shell in tzselect now defaults to /bin/bash, but this can
4498  be overridden by specifying KSHELL.
4499  The main web page now mentions the unofficial GitHub repository.
4500  (Thanks to Mike Frysinger.)
4501
4502  Tarball signatures can now be built by running 'make signatures'.
4503  There are also new makefile rules 'tarballs', 'check_public', and
4504  separate makefile rules for each tarball and signature file.
4505  A few makefile rules are now more portable to strict POSIX.
4506
4507  The main web page now lists the canonical IANA URL.
4508
4509
4510Release 2012h - 2012-10-26 22:49:10 -0700
4511
4512  Bahia no longer has DST.  (Thanks to Kelley Cook.)
4513
4514  Tocantins has DST.  (Thanks to Rodrigo Severo.)
4515
4516  Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
4517
4518  Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
4519
4520  Web page updates.
4521
4522  More C modernization, except that at Arthur David Olson's suggestion
4523  the instances of 'register' were kept.
4524
4525
4526Release 2012g - 2012-10-17 20:59:45 -0700
4527
4528  Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
4529
4530  Palestine fall 2012.  (Thanks to Steffen Thorsen.)
4531
4532  Assume C89.
4533
4534  To attack the version-number problem, this release ships the file
4535  'Makefile' (which contains the release number) in both the tzcode and
4536  the tzdata tarballs.  The two Makefiles are identical, and should be
4537  identical in any matching pair of tarballs, so it shouldn't matter
4538  which order you extract the tarballs.  Perhaps we can come up with a
4539  better version-number scheme at some point; this scheme does have the
4540  virtue of not adding more files.
4541
4542
4543Release 2012f - 2012-09-12 23:17:03 -0700
4544
4545  * australasia (Pacific/Fiji): Fiji DST is October 21 through January
4546    20 this year.  (Thanks to Steffen Thorsen.)
4547
4548
4549Release 2012e - 2012-08-02 20:44:55 -0700
4550
4551  * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
4552    (Thanks to Steffen Thorsen.)
4553
4554  * Use a single version number for both code and data.
4555
4556  * .gitignore: New file.
4557
4558  * Remove trailing white space.
4559
4560
4561Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
4562
4563  Changes for Morocco's timestamps, which take effect in a couple of
4564  hours, along with infrastructure changes to accommodate how the tz
4565  code and data are released on IANA.
4566
4567
4568Release data2012c - 2012-03-27 12:17:25 -0400
4569
4570  africa
4571	Summer time changes for Morocco (to start late April 2012)
4572
4573  asia
4574	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
4575
4576  northamerica
4577	Haiti following US/Canada rules for 2012 (and we're assuming,
4578	for now anyway, for the future).
4579
4580
4581Release 2012b - 2012-03-02 12:29:15 +0700
4582
4583  There is just one change to tzcode2012b (compared with 2012a):
4584  the Makefile that was accidentally included with 2012a has been
4585  replaced with the version that should have been there, which is
4586  identical with the previous version (from tzcode2011i).
4587
4588  There are just two changes in tzdata2012b compared with 2012a.
4589
4590  Most significantly, summer time in Cuba has been delayed 3 weeks
4591  (now starts April 1 rather than March 11).   Since Mar 11 (the old start
4592  date, as listed in 2012a) is just a little over a week away, this
4593  change is urgent.
4594
4595  Less importantly, an excess tab in one of the changes in zone.tab
4596  in 2012a has been removed.
4597
4598
4599Release 2012a - 2012-03-01 18:28:10 +0700
4600
4601  The changes in tzcode2012a (compared to the previous version, 2011i)
4602  are entirely to the README and tz-art.htm and tz-link.htm files, if
4603  none of those concern you, you can ignore the code update.  The changes
4604  reflect the changed addresses for the mailing list and the code and
4605  data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
4606  has been added to tz-link.htm).
4607
4608  In tzdata2012a (compared to the previous release, which was 2011n)
4609  the major changes are:
4610	Chile 2011/2012 and 2012/2013 summer time date adjustments.
4611	Falkland Islands onto permanent summer time (we're assuming for the
4612		foreseeable future, though 2012 is all we're fairly certain of.)
4613	Armenia has abolished Summer Time.
4614	Tokelau jumped the International Date Line back last December
4615		(just the same as their near neighbour, Samoa).
4616	America/Creston is a new zone for a small area of British Columbia
4617	There will be a leapsecond 2012-06-30 23:59:60 UTC.
4618
4619  Other minor changes are:
4620	Corrections to 1918 Canadian summer time end dates.
4621	Updated URL for UK time zone history (in comments)
4622	A few typos in Le Corre's list of free French place names (comments)
4623
4624
4625Release data2011n - 2011-10-30 14:57:54 +0700
4626
4627  There are three changes of note - most urgently, Cuba (America/Havana)
4628  has extended summer time by two weeks, now to end on Nov 13, rather than
4629  the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
4630  (Europe/Tiraspol) decided not to split from the rest of Moldova after
4631  all, and consequently that zone has been removed (again) and reinstated
4632  in the "backward" file as a link to Europe/Chisinau.   And third, the
4633  end date for Fiji's summer time this summer was moved forward from the
4634  earlier planned Feb 26, to Jan 22.
4635
4636  Apart from that, Moldova (MD) returns to a single entry in zone.tab
4637  (and the incorrect syntax that was in the 2011m version of that file
4638  is so fixed - it would have been fixed in a different way had this
4639  change not happened - that's the "missing" sccs version id).
4640
4641
4642Release data2011m - 2011-10-24 21:42:16 +0700
4643
4644  In particular, the typos in comments in the data (2011-11-17 should have
4645  been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
4646  Tim Parenti noted) have been fixed, and the change for Ukraine has been
4647  made in all 4 Ukrainian zones, rather than just Europe/Kiev
4648  (again, thanks to Tim Parenti, and also Denys Gavrysh).
4649
4650  In addition, I added Europe/Tiraspol to zone.tab.
4651
4652  This time, all the files have new version numbers...  (including the files
4653  otherwise unchanged in 2011m that were changed in 2011l but didn't get new
4654  version numbers there...)
4655
4656
4657Release data2011l - 2011-10-10 11:15:43 +0700
4658
4659  There are just 2 changes that cause different generated tzdata files from
4660  zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
4661  is included, but commented out.  Compared with the diff I sent out last week,
4662  this version also includes attributions for the sources for the changes
4663  (in much the same format as ado used, but the html tags have not been
4664  checked, verified, or used in any way at all, so if there are errors there,
4665  please let me know.)
4666
4667
4668Release data2011k - 2011-09-20 17:54:03 -0400
4669
4670  [not summarized]
4671
4672
4673Release data2011j - 2011-09-12 09:22:49 -0400
4674
4675  (contemporary changes for Samoa; past changes for Kenya, Uganda, and
4676  Tanzania); there are also two spelling corrections to comments in
4677  the australasia file (with thanks to Christos Zoulas).
4678
4679
4680Release 2011i - 2011-08-29 05:56:32 -0400
4681
4682  [not summarized]
4683
4684
4685Release data2011h - 2011-06-15 18:41:48 -0400
4686
4687  Russia and Curaçao changes
4688
4689
4690Release 2011g - 2011-04-25 09:07:22 -0400
4691
4692  update the rules for Egypt to reflect its abandonment of DST this year
4693
4694
4695Release 2011f - 2011-04-06 17:14:53 -0400
4696
4697  [not summarized]
4698
4699
4700Release 2011e - 2011-03-31 16:04:38 -0400
4701
4702  Morocco, Chile, and tz-link changes
4703
4704
4705Release 2011d - 2011-03-14 09:18:01 -0400
4706
4707  changes that impact present-day timestamps in Cuba, Samoa, and Turkey
4708
4709
4710Release 2011c - 2011-03-07 09:30:09 -0500
4711
4712  These do affect current timestamps in Chile and Annette Island, Canada.
4713
4714
4715Release 2011b - 2011-02-07 08:44:50 -0500
4716
4717  [not summarized]
4718
4719
4720Release 2011a - 2011-01-24 10:30:16 -0500
4721
4722  [not summarized]
4723
4724
4725Release data2010o - 2010-11-01 09:18:23 -0400
4726
4727  change to the end of DST in Fiji in 2011
4728
4729
4730Release 2010n - 2010-10-25 08:19:17 -0400
4731
4732  [not summarized]
4733
4734
4735Release 2010m - 2010-09-27 09:24:48 -0400
4736
4737  Hong Kong, Vostok, and zic.c changes
4738
4739
4740Release 2010l - 2010-08-16 06:57:25 -0400
4741
4742  [not summarized]
4743
4744
4745Release 2010k - 2010-07-26 10:42:27 -0400
4746
4747  [not summarized]
4748
4749
4750Release 2010j - 2010-05-10 09:07:48 -0400
4751
4752  changes for Bahía de Banderas and for version naming
4753
4754
4755Release data2010i - 2010-04-16 18:50:45 -0400
4756
4757  the end of DST in Morocco on 2010-08-08
4758
4759
4760Release data2010h - 2010-04-05 09:58:56 -0400
4761
4762  [not summarized]
4763
4764
4765Release data2010g - 2010-03-24 11:14:53 -0400
4766
4767  [not summarized]
4768
4769
4770Release 2010f - 2010-03-22 09:45:46 -0400
4771
4772  [not summarized]
4773
4774
4775Release data2010e - 2010-03-08 14:24:27 -0500
4776
4777  corrects the Dhaka bug found by Danvin Ruangchan
4778
4779
4780Release data2010d - 2010-03-06 07:26:01 -0500
4781
4782  [not summarized]
4783
4784
4785Release 2010c - 2010-03-01 09:20:58 -0500
4786
4787  changes including KRE's suggestion for earlier initialization of
4788  "goahead" and "goback" structure elements
4789
4790
4791Release code2010a - 2010-02-16 10:40:04 -0500
4792
4793  [not summarized]
4794
4795
4796Release data2010b - 2010-01-20 12:37:01 -0500
4797
4798  Mexico changes
4799
4800
4801Release data2010a - 2010-01-18 08:30:04 -0500
4802
4803  changes to Dhaka
4804
4805
4806Release data2009u - 2009-12-26 08:32:28 -0500
4807
4808  changes to DST in Bangladesh
4809
4810
4811Release 2009t - 2009-12-21 13:24:27 -0500
4812
4813  [not summarized]
4814
4815
4816Release data2009s - 2009-11-14 10:26:32 -0500
4817
4818  (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
4819
4820
4821Release 2009r - 2009-11-09 10:10:31 -0500
4822
4823  "antarctica" and "tz-link.htm" changes
4824
4825
4826Release 2009q - 2009-11-02 09:12:40 -0500
4827
4828  with two corrections as reported by Eric Muller and Philip Newton
4829
4830
4831Release data2009p - 2009-10-23 15:05:27 -0400
4832
4833  Argentina (including San Luis) changes (with the correction from
4834  Mariano Absatz)
4835
4836
4837Release data2009o - 2009-10-14 16:49:38 -0400
4838
4839  Samoa (commentary only), Pakistan, and Bangladesh changes
4840
4841
4842Release data2009n - 2009-09-22 15:13:38 -0400
4843
4844  added commentary for Argentina and a change to the end of DST in
4845  2009 in Pakistan
4846
4847
4848Release data2009m - 2009-09-03 10:23:43 -0400
4849
4850  Samoa and Palestine changes
4851
4852
4853Release data2009l - 2009-08-14 09:13:07 -0400
4854
4855  Samoa (comments only) and Egypt
4856
4857
4858Release 2009k - 2009-07-20 09:46:08 -0400
4859
4860  [not summarized]
4861
4862
4863Release data2009j - 2009-06-15 06:43:59 -0400
4864
4865  Bangladesh change (with a short turnaround since the DST change is
4866  impending)
4867
4868
4869Release 2009i - 2009-06-08 09:21:22 -0400
4870
4871  updating for DST in Bangladesh this year
4872
4873
4874Release 2009h - 2009-05-26 09:19:14 -0400
4875
4876  [not summarized]
4877
4878
4879Release data2009g - 2009-04-20 16:34:07 -0400
4880
4881  Cairo
4882
4883
4884Release data2009f - 2009-04-10 11:00:52 -0400
4885
4886  correct DST in Pakistan
4887
4888
4889Release 2009e - 2009-04-06 09:08:11 -0400
4890
4891  [not summarized]
4892
4893
4894Release 2009d - 2009-03-23 09:38:12 -0400
4895
4896  Morocco, Tunisia, Argentina, and American Astronomical Society changes
4897
4898
4899Release data2009c - 2009-03-16 09:47:51 -0400
4900
4901  change to the start of Cuban DST
4902
4903
4904Release 2009b - 2009-02-09 11:15:22 -0500
4905
4906  [not summarized]
4907
4908
4909Release 2009a - 2009-01-21 10:09:39 -0500
4910
4911  [not summarized]
4912
4913
4914Release data2008i - 2008-10-21 12:10:25 -0400
4915
4916  southamerica and zone.tab files, with Argentina DST rule changes and
4917  United States zone reordering and recommenting
4918
4919
4920Release 2008h - 2008-10-13 07:33:56 -0400
4921
4922  [not summarized]
4923
4924
4925Release 2008g - 2008-10-06 09:03:18 -0400
4926
4927  Fix a broken HTML anchor and update Brazil's DST transitions;
4928  there's also a slight reordering of information in tz-art.htm.
4929
4930
4931Release data2008f - 2008-09-09 22:33:26 -0400
4932
4933  [not summarized]
4934
4935
4936Release 2008e - 2008-07-28 14:11:17 -0400
4937
4938  changes by Arthur David Olson and Jesper Nørgaard Welen
4939
4940
4941Release data2008d - 2008-07-07 09:51:38 -0400
4942
4943  changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
4944
4945
4946Release data2008c - 2008-05-19 17:48:03 -0400
4947
4948  Pakistan, Morocco, and Mongolia
4949
4950
4951Release data2008b - 2008-03-24 08:30:59 -0400
4952
4953  including renaming Asia/Calcutta to Asia/Kolkata, with a backward
4954  link provided
4955
4956
4957Release 2008a - 2008-03-08 05:42:16 -0500
4958
4959  [not summarized]
4960
4961
4962Release 2007k - 2007-12-31 10:25:22 -0500
4963
4964  most importantly, changes to the "southamerica" file based on
4965  Argentina's readoption of daylight saving time
4966
4967
4968Release 2007j - 2007-12-03 09:51:01 -0500
4969
4970  1. eliminate the "P" (parameter) macro;
4971
4972  2. the "noncontroversial" changes circulated on the time zone
4973  mailing list (less the changes to "logwtmp.c");
4974
4975  3. eliminate "too many transition" errors when "min" is used in time
4976  zone rules;
4977
4978  4. changes by Paul Eggert (including updated information for Venezuela).
4979
4980
4981Release data2007i - 2007-10-30 10:28:11 -0400
4982
4983  changes for Cuba and Syria
4984
4985
4986Release 2007h - 2007-10-01 10:05:51 -0400
4987
4988  changes by Paul Eggert, as well as an updated link to the ICU
4989  project in tz-link.htm
4990
4991
4992Release 2007g - 2007-08-20 10:47:59 -0400
4993
4994  changes by Paul Eggert
4995
4996  The "leapseconds" file has been updated to incorporate the most
4997  recent International Earth Rotation and Reference Systems Service
4998  (IERS) bulletin.
4999
5000  There's an addition to tz-art.htm regarding the television show "Medium".
5001
5002
5003Release 2007f - 2007-05-07 10:46:46 -0400
5004
5005  changes by Paul Eggert (including Haiti, Turks and Caicos, and New
5006  Zealand)
5007
5008  changes to zic.c to allow hour values greater than 24 (along with
5009  Paul's improved time value overflow checking)
5010
5011
5012Release 2007e - 2007-04-02 10:11:52 -0400
5013
5014  Syria and Honduras changes by Paul Eggert
5015
5016  zic.c variable renaming changes by Arthur David Olson
5017
5018
5019Release 2007d - 2007-03-20 08:48:30 -0400
5020
5021  changes by Paul Eggert
5022
5023  the elimination of white space at the ends of lines
5024
5025
5026Release 2007c - 2007-02-26 09:09:37 -0500
5027
5028  changes by Paul Eggert
5029
5030
5031Release 2007b - 2007-02-12 09:34:20 -0500
5032
5033  Paul Eggert's proposed change to the quotation handling logic in zic.c.
5034
5035  changes to the commentary in "leapseconds" reflecting the IERS
5036  announcement that there is to be no positive leap second at the end
5037  of June 2007.
5038
5039
5040Release 2007a - 2007-01-08 12:28:29 -0500
5041
5042  changes by Paul Eggert
5043
5044  Derick Rethans's Asmara change
5045
5046  Oscar van Vlijmen's Easter Island local mean time change
5047
5048  symbolic link changes
5049
5050
5051Release 2006p - 2006-11-27 08:54:27 -0500
5052
5053  changes by Paul Eggert
5054
5055
5056Release 2006o - 2006-11-06 09:18:07 -0500
5057
5058  changes by Paul Eggert
5059
5060
5061Release 2006n - 2006-10-10 11:32:06 -0400
5062
5063  changes by Paul Eggert
5064
5065
5066Release 2006m - 2006-10-02 15:32:35 -0400
5067
5068  changes for Uruguay, Palestine, and Egypt by Paul Eggert
5069
5070  (minimalist) changes to zic.8 to clarify "until" information
5071
5072
5073Release data2006l - 2006-09-18 12:58:11 -0400
5074
5075  Paul's best-effort work on this coming weekend's Egypt time change
5076
5077
5078Release 2006k - 2006-08-28 12:19:09 -0400
5079
5080  changes by Paul Eggert
5081
5082
5083Release 2006j - 2006-08-21 09:56:32 -0400
5084
5085  changes by Paul Eggert
5086
5087
5088Release code2006i - 2006-08-07 12:30:55 -0400
5089
5090  localtime.c fixes
5091
5092  Ken Pizzini's conversion script
5093
5094
5095Release code2006h - 2006-07-24 09:19:37 -0400
5096
5097  adds public domain notices to four files
5098
5099  includes a fix for transition times being off by a second
5100
5101  adds a new recording to the "arts" file (information courtesy Colin Bowern)
5102
5103
5104Release 2006g - 2006-05-08 17:18:09 -0400
5105
5106  northamerica changes by Paul Eggert
5107
5108
5109Release 2006f - 2006-05-01 11:46:00 -0400
5110
5111  a missing version number problem is fixed (with thanks to Bradley
5112  White for catching the problem)
5113
5114
5115Release 2006d - 2006-04-17 14:33:43 -0400
5116
5117  changes by Paul Eggert
5118
5119  added new items to tz-arts.htm that were found by Paul
5120
5121
5122Release 2006c - 2006-04-03 10:09:32 -0400
5123
5124  two sets of data changes by Paul Eggert
5125
5126  a fencepost error fix in zic.c
5127
5128  changes to zic.c and the "europe" file to minimize differences
5129  between output produced by the old 32-bit zic and the new 64-bit
5130  version
5131
5132
5133Release 2006b - 2006-02-20 10:08:18 -0500
5134  [tz32code2006b + tz64code2006b + tzdata2006b]
5135
5136  64-bit code
5137
5138  All SCCS IDs were bumped to "8.1" for this release.
5139
5140
5141Release 2006a - 2006-01-30 08:59:31 -0500
5142
5143  changes by Paul Eggert (in particular, Indiana time zone moves)
5144
5145  an addition to the zic manual page to describe how special-case
5146  transitions are handled
5147
5148
5149Release 2005r - 2005-12-27 09:27:13 -0500
5150
5151  Canadian changes by Paul Eggert
5152
5153  They also add "<pre>" directives to time zone data files and reflect
5154  changes to warning message logic in "zdump.c" (but with calls to
5155  "gettext" kept unbundled at the suggestion of Ken Pizzini).
5156
5157
5158Release 2005q - 2005-12-13 09:17:09 -0500
5159
5160  Nothing earth-shaking here:
5161	1.  Electronic mail addresses have been removed.
5162	2.  Casts of the return value of exit have been removed.
5163	3.  Casts of the argument of is.* macros have been added.
5164	4.  Indentation in one section of zic.c has been fixed.
5165	5.  References to dead URLs in the data files have been dealt with.
5166
5167
5168Release 2005p - 2005-12-05 10:30:53 -0500
5169
5170  "systemv", "tz-link.htm", and "zdump.c" changes
5171  (less the casts of arguments to the is* macros)
5172
5173
5174Release 2005o - 2005-11-28 10:55:26 -0500
5175
5176  Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
5177
5178  zdump.c lint fixes by Arthur David Olson
5179
5180
5181Release 2005n - 2005-10-03 09:44:09 -0400
5182
5183  changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
5184  et al. changes)
5185
5186
5187Release 2005m - 2005-08-29 12:15:40 -0400
5188
5189  changes by Paul Eggert (with a small tweak to the tz-art change)
5190
5191  a declaration of an unused variable has been removed from zdump.c
5192
5193
5194Release 2005l - 2005-08-22 12:06:39 -0400
5195
5196  changes by Paul Eggert
5197
5198  overflow/underflow checks by Arthur David Olson, minus changes to
5199  the "Theory" file about the pending addition of 64-bit data (I grow
5200  less confident of the changes being accepted with each passing day,
5201  and the changes no longer increase the data files nine-fold--there's
5202  less than a doubling in size by my local Sun's reckoning)
5203
5204
5205Release 2005k - 2005-07-14 14:14:24 -0400
5206
5207  The "leapseconds" file has been edited to reflect the recently
5208  announced leap second at the end of 2005.
5209
5210  I've also deleted electronic mail addresses from the files as an
5211  anti-spam measure.
5212
5213
5214Release 2005j - 2005-06-13 14:34:13 -0400
5215
5216  These reflect changes to limit the length of time zone abbreviations
5217  and the characters used in those abbreviations.
5218
5219  There are also changes to handle POSIX-style "quoted" timezone
5220  environment variables.
5221
5222  The changes were circulated on the time zone mailing list; the only
5223  change since then was the removal of a couple of minimum-length of
5224  abbreviation checks.
5225
5226
5227Release data2005i - 2005-04-21 15:04:16 -0400
5228
5229  changes (most importantly to Nicaragua and Haiti) by Paul Eggert
5230
5231
5232Release 2005h - 2005-04-04 11:24:47 -0400
5233
5234  changes by Paul Eggert
5235
5236  minor changes to Makefile and zdump.c to produce more useful output
5237  when doing a "make typecheck"
5238
5239
5240Release 2005g - 2005-03-14 10:11:21 -0500
5241
5242  changes by Paul Eggert (a change to current DST rules in Uruguay and
5243  an update to a link to time zone software)
5244
5245
5246Release 2005f - 2005-03-01 08:45:32 -0500
5247
5248  data and documentation changes by Paul Eggert
5249
5250
5251Release 2005e - 2005-02-10 15:59:44 -0500
5252
5253  [not summarized]
5254
5255
5256Release code2005d - 2005-01-31 09:21:47 -0500
5257
5258  make zic complain about links to links if the -v flag is used
5259
5260  have "make public" do more code checking
5261
5262  add an include to "localtime.c" for the benefit of gcc systems
5263
5264
5265Release 2005c - 2005-01-17 18:36:29 -0500
5266
5267  get better results when mktime runs on a system where time_t is double
5268
5269  changes to the data files (most importantly to Paraguay)
5270
5271
5272Release 2005b - 2005-01-10 09:19:54 -0500
5273
5274  Get localtime and gmtime working on systems with exotic time_t types.
5275
5276  Update the leap second commentary in the "leapseconds" file.
5277
5278
5279Release 2005a - 2005-01-01 13:13:44 -0500
5280
5281  [not summarized]
5282
5283
5284Release code2004i - 2004-12-14 13:42:58 -0500
5285
5286  Deal with systems where time_t is unsigned.
5287
5288
5289Release code2004h - 2004-12-07 11:40:18 -0500
5290
5291  64-bit-time_t changes
5292
5293
5294Release 2004g - 2004-11-02 09:06:01 -0500
5295
5296  update to Cuba (taking effect this weekend)
5297
5298  other changes by Paul Eggert
5299
5300  correction of the spelling of Oslo
5301
5302  changed versions of difftime.c and private.h
5303
5304
5305Release code2004f - 2004-10-21 10:25:22 -0400
5306
5307  Cope with wide-ranging tm_year values.
5308
5309
5310Release 2004e - 2004-10-11 14:47:21 -0400
5311
5312  Brazil/Argentina/Israel changes by Paul Eggert
5313
5314  changes to tz-link.htm by Paul
5315
5316  one small fix to Makefile
5317
5318
5319Release 2004d - 2004-09-22 08:27:29 -0400
5320
5321  Avoid overflow problems when TM_YEAR_BASE is added to an integer.
5322
5323
5324Release 2004c - 2004-08-11 12:06:26 -0400
5325
5326  asctime-related changes
5327
5328  (variants of) some of the documentation changes suggested by Paul Eggert
5329
5330
5331Release 2004b - 2004-07-19 14:33:35 -0400
5332
5333  data changes by Paul Eggert - most importantly, updates for Argentina
5334
5335
5336Release 2004a - 2004-05-27 12:00:47 -0400
5337
5338  changes by Paul Eggert
5339
5340  Handle DST transitions that occur at the end of a month in some
5341  years but at the start of the following month in other years.
5342
5343  Add a copy of the correspondence that's the basis for claims about
5344  DST in the Navajo Nation.
5345
5346
5347Release 2003e - 2003-12-15 09:36:47 -0500
5348
5349  changes by Arthur David Olson (primarily code changes)
5350
5351  changes by Paul Eggert (primarily data changes)
5352
5353  minor changes to "Makefile" and "northamerica" (in the latter case,
5354  optimization of the "Toronto" rules)
5355
5356
5357Release 2003d - 2003-10-06 09:34:44 -0400
5358
5359  changes by Paul Eggert
5360
5361
5362Release 2003c - 2003-09-16 10:47:05 -0400
5363
5364  Fix bad returns in zic.c's inleap function.
5365  Thanks to Bradley White for catching the problem!
5366
5367
5368Release 2003b - 2003-09-16 07:13:44 -0400
5369
5370  Add a "--version" option (and documentation) to the zic and zdump commands.
5371
5372  changes to overflow/underflow checking in zic
5373
5374  a localtime typo fix.
5375
5376  Update the leapseconds and tz-art.htm files.
5377
5378
5379Release 2003a - 2003-03-24 09:30:54 -0500
5380
5381  changes by Paul Eggert
5382
5383  a few additions and modifications to the tz-art.htm file
5384
5385
5386Release 2002d - 2002-10-15 13:12:42 -0400
5387
5388  changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
5389
5390  There's also a new time zone quote in "tz-art.htm".
5391
5392
5393Release 2002c - 2002-04-04 11:55:20 -0500
5394
5395  changes by Paul Eggert
5396
5397  Change zic.c to avoid creating symlinks to files that don't exist.
5398
5399
5400Release 2002b - 2002-01-28 12:56:03 -0500
5401
5402  [These change notes are for Release 2002a, which was corrupted.
5403  2002b was a corrected version of 2002a.]
5404
5405  changes by Paul Eggert
5406
5407  Update the "leapseconds" file to note that there'll be no leap
5408  second at the end of June, 2002.
5409
5410  Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
5411
5412  Change to "difftime.c" to avoid sizeof problems.
5413
5414
5415Release 2001d - 2001-10-09 13:31:32 -0400
5416
5417  changes by Paul Eggert
5418
5419
5420Release 2001c - 2001-06-05 13:59:55 -0400
5421
5422  changes by Paul Eggert and Andrew Brown
5423
5424
5425Release 2001b - 2001-04-05 16:44:38 -0400
5426
5427  changes by Paul Eggert (modulo jnorgard's typo fix)
5428
5429  tz-art.htm has been HTMLified.
5430
5431
5432Release 2001a - 2001-03-13 12:57:44 -0500
5433
5434  changes by Paul Eggert
5435
5436  An addition to the "leapseconds" file: comments with the text of the
5437  latest IERS leap second notice.
5438
5439  Trailing white space has been removed from data file lines, and
5440  repeated spaces in "Rule Jordan" lines in the "asia" file have been
5441  converted to tabs.
5442
5443
5444Release 2000h - 2000-12-14 15:33:38 -0500
5445
5446  changes by Paul Eggert
5447
5448  one typo fix in the "art" file
5449
5450  With providence, this is the last update of the millennium.
5451
5452
5453Release 2000g - 2000-10-10 11:35:22 -0400
5454
5455  changes by Paul Eggert
5456
5457  correction of John Mackin's name submitted by Robert Elz
5458
5459  Garry Shandling's Daylight Saving Time joke (!?!) from the recent
5460  Emmy Awards broadcast.
5461
5462
5463Release 2000f - 2000-08-10 09:31:58 -0400
5464
5465  changes by Paul Eggert
5466
5467  Added information in "tz-art.htm" on a Seinfeld reference to DST.
5468
5469  Error checking and messages in the "yearistype" script have been
5470  improved.
5471
5472
5473Release 2000e - 2000-07-31 09:27:54 -0400
5474
5475  data changes by Paul Eggert
5476
5477  a change to the default value of the defined constant HAVE_STRERROR
5478
5479  the addition of a Dave Barry quote on DST to the tz-arts file
5480
5481
5482Release 2000d - 2000-04-20 15:43:04 -0400
5483
5484  changes to the documentation and code of strftime for C99 conformance
5485
5486  a bug fix for date.c
5487
5488  These are based on (though modified from) changes by Paul Eggert.
5489
5490
5491Release 2000c - 2000-03-04 10:31:43 -0500
5492
5493  changes by Paul Eggert
5494
5495
5496Release 2000b - 2000-02-21 12:16:29 -0500
5497
5498  changes by Paul Eggert and Joseph Myers
5499
5500  modest tweaks to the tz-art.htm and tz-link.htm files
5501
5502
5503Release 2000a - 2000-01-18 09:21:26 -0500
5504
5505  changes by Paul Eggert
5506
5507  The two hypertext documents have also been renamed.
5508
5509
5510Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
5511
5512  Paul Eggert's changes
5513
5514  additions to the "zic" manual page and the "Arts.htm" file
5515
5516
5517Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
5518
5519  [not summarized]
5520
5521
5522Release data1999h - 1999-10-07 03:50:29 -0400
5523
5524  changes by Paul Eggert to "europe" (most importantly, fixing
5525  Lithuania and Estonia)
5526
5527
5528Release 1999g - 1999-09-28 11:06:18 -0400
5529
5530  data changes by Paul Eggert (most importantly, the change for
5531  Lebanon that buys correctness for this coming Sunday)
5532
5533  The "code" file contains changes to "Makefile" and "checktab.awk" to
5534  allow better checking of time zone files before they are published.
5535
5536
5537Release 1999f - 1999-09-23 09:48:14 -0400
5538
5539  changes by Arthur David Olson and Paul Eggert
5540
5541
5542Release 1999e - 1999-08-17 15:20:54 -0400
5543
5544  changes circulated by Paul Eggert, although the change to handling
5545  of DST-specifying timezone names has been commented out for now
5546  (search for "XXX" in "localtime.c" for details).  These files also
5547  do not make any changes to the start of DST in Brazil.
5548
5549  In addition to Paul's changes, there are updates to "Arts.htm" and
5550  cleanups of URLs.
5551
5552
5553Release 1999d - 1999-03-30 11:31:07 -0500
5554
5555  changes by Paul Eggert
5556
5557  The Makefile's "make public" rule has also been changed to do a test
5558  compile of each individual time zone data file (which should help
5559  avoid problems such as the one we had with Nicosia).
5560
5561
5562Release 1999c - 1999-03-25 09:47:47 -0500
5563
5564  changes by Paul Eggert, most importantly the change for Chile.
5565
5566
5567Release 1999b - 1999-02-01 17:51:44 -0500
5568
5569  changes by Paul Eggert
5570
5571  code changes (suggested by Mani Varadarajan, mani at be.com) for
5572  correct handling of symbolic links when building using a relative directory
5573
5574  code changes to generate correct messages for failed links
5575
5576  updates to the URLs in Arts.htm
5577
5578
5579Release 1999a - 1999-01-19 16:20:29 -0500
5580
5581  error message internationalizations and corrections in zic.c and
5582  zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
5583  to whom thanks!)
5584
5585
5586Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
5587
5588  changes for Brazil, Chile, and Germany
5589
5590  support for use of "24:00" in the input files for the time zone compiler
5591
5592
5593Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
5594
5595  changes by Paul Eggert
5596
5597  correction to a define in the "private.h" file
5598
5599
5600Release data1998g - 1998-08-11 03:28:35 -0000
5601  [tzdata1998g.tar.gz is missing!]
5602
5603  Lithuanian change provided by mgedmin at pub.osf.it
5604
5605  Move creation of the GMT link with Etc/GMT to "etcetera" (from
5606  "backward") to ensure that the GMT file is created even where folks
5607  don't want the "backward" links (as suggested by Paul Eggert).
5608
5609
5610Release data1998f - 1998-07-20 13:50:00 -0000
5611  [tzdata1998f.tar.gz is missing!]
5612
5613  Update the "leapseconds" file to include the newly announced
5614  insertion at the end of 1998.
5615
5616
5617Release code1998f - 1998-06-01 10:18:31 -0400
5618
5619  addition to localtime.c by Guy Harris
5620
5621
5622Release 1998e - 1998-05-28 09:56:26 -0400
5623
5624  The Makefile is changed to produce zoneinfo-posix rather than
5625  zoneinfo/posix, and to produce zoneinfo-leaps rather than
5626  zoneinfo/right.
5627
5628  data changes by Paul Eggert
5629
5630  changes from Guy Harris to provide asctime_r and ctime_r
5631
5632  A usno1998 file (substantially identical to usno1997) has been added.
5633
5634
5635Release 1998d - 1998-05-14 11:58:34 -0400
5636
5637  changes to comments (in particular, elimination of references to CIA maps).
5638  "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
5639  where changes occur.
5640
5641
5642Release 1998c - 1998-02-28 12:32:26 -0500
5643
5644  changes by Paul Eggert (save the "French correction," on which I'll
5645  wait for the dust to settle)
5646
5647  symlink changes
5648
5649  changes and additions to Arts.htm
5650
5651
5652Release 1998b - 1998-01-17 14:31:51 -0500
5653
5654  URL cleanups and additions
5655
5656
5657Release 1998a - 1998-01-13 12:37:35 -0500
5658
5659  changes by Paul Eggert
5660
5661
5662Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
5663
5664  changes by Paul Eggert, with minor modifications from Arthur David
5665  Olson to make the files more browser friendly
5666
5667
5668Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
5669
5670  minor changes to put "TZif" at the start of each timezone information file
5671
5672  a rule has also been added to the Makefile so you can
5673	make zones
5674  to just recompile the zone information files (rather than doing a
5675  full "make install" with its other effects).
5676
5677
5678Release data1997i - 1997-10-07 08:45:38 -0400
5679
5680  changes to Africa by Paul Eggert
5681
5682
5683Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
5684
5685  corrections for Uruguay (and other locations)
5686
5687  Arthur David Olson's simple-minded fix allowing mktime to both
5688  correctly handle leap seconds and correctly handle tm_sec values
5689  upon which arithmetic has been performed.
5690
5691
5692Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
5693
5694  Paul Eggert's updates
5695
5696  a small change to a function prototype;
5697
5698  "Music" has been renamed "Arts.htm", HTMLified, and augmented to
5699  include information on Around the World in Eighty Days.
5700
5701
5702Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
5703
5704  fixes to zic's error handling
5705
5706  changes inspired by the item circulated on Slovenia
5707
5708  The description of Web resources has been HTMLified for browsing
5709  convenience.
5710
5711  A new piece of tz-related music has been added to the "Music" file.
5712
5713
5714Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
5715
5716  Paul Eggert's latest suggestions
5717
5718
5719Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
5720
5721  changes to "zic.c" to correct performance of the "-s" option
5722
5723  a new file "usno1997"
5724
5725
5726Release data1997c - 1997-03-04 09:58:18 -0500
5727
5728  changes in Israel
5729
5730
5731Release 1997b - 1997-02-27 18:34:19 -0500
5732
5733  The data file incorporates the 1997 leap second.
5734
5735  The code file incorporates Arthur David Olson's take on the
5736  zic/multiprocessor/directory-creation situation.
5737
5738
5739Release 1997a - 1997-01-21 09:11:10 -0500
5740
5741  Paul Eggert's Antarctica (and other changes)
5742
5743  Arthur David Olson finessed the "getopt" issue by checking against
5744  both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
5745  is returned while SunOS 5.5's manual says EOF is returned).
5746
5747
5748Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
5749
5750  Paul Eggert's latest changes
5751
5752
5753Release code1996n - 1996-12-16 09:42:02 -0500
5754
5755  link snapping fix from Bruce Evans (via Garrett Wollman)
5756
5757
5758Release data1996m - 1996-11-24 02:37:34 -0000
5759  [tzdata1996m.tar.gz is missing!]
5760
5761  Paul Eggert's batch of changes
5762
5763
5764Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
5765
5766  No functional changes here; the files have simply been changed to
5767  make more use of ISO style dates in comments. The names of the above
5768  files now include the year in full.
5769
5770
5771Release code96l - 1996-09-08 17:12:20 -0400
5772
5773  tzcode96k was missing a couple of pieces.
5774
5775
5776Release 96k - 1996-09-08 16:06:22 -0400
5777
5778  the latest round of changes from Paul Eggert
5779
5780  the recent Year 2000 material
5781
5782
5783Release code96j - 1996-07-30 13:18:53 -0400
5784
5785  Set sp->typecnt as suggested by Timothy Patrick Murphy.
5786
5787
5788Release code96i - 1996-07-27 20:11:35 -0400
5789
5790  Paul's suggested patch for strftime %V week numbers
5791
5792
5793Release data96i - 1996-07-01 18:13:04 -0400
5794
5795  "northamerica" and "europe" changes by Paul Eggert
5796
5797
5798Release code96h - 1996-06-05 08:02:21 -0400
5799
5800  fix for handling transitions specified in Universal Time
5801
5802  Some "public domain" notices have also been added.
5803
5804
5805Release code96g - 1996-05-16 14:00:26 -0400
5806
5807  fix for the simultaneous-DST-and-zone-change challenge
5808
5809
5810Release data96h - 1996-05-09 17:40:51 -0400
5811
5812  changes by Paul Eggert
5813
5814
5815Release code96f-data96g - 1996-05-03 03:09:59 -0000
5816  [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
5817
5818  The changes get us some of the way to fixing the problems noted in Paul
5819  Eggert's letter yesterday (in addition to a few others).  The approach
5820  has been to make zic a bit smarter about figuring out what time zone
5821  abbreviations apply just after the time specified in the "UNTIL" part
5822  of a zone line.  Putting the smarts in zic means avoiding having
5823  transition times show up in both "Zone" lines and "Rule" lines, which
5824  in turn avoids multiple transition time entries in time zone files.
5825  (This also makes the zic input files such as "europe" a bit shorter and
5826  should ease maintenance.)
5827
5828
5829Release data96f - 1996-04-19 19:20:03 -0000
5830  [tzdata96f.tar.gz is missing!]
5831
5832  The only changes are to the "northamerica" file; the time zone
5833  abbreviation for Denver is corrected to MST (and MDT), and the
5834  comments for Mexico have been updated.
5835
5836
5837Release data96e - 1996-03-19 17:37:26 -0500
5838
5839  Proposals by Paul Eggert, in particular the Portugal change that
5840  comes into play at the end of this month.
5841
5842
5843Release data96d - 1996-03-18 20:49:39 -0500
5844
5845  [not summarized]
5846
5847
5848Release code96e - 1996-02-29 15:43:27 -0000
5849  [tzcode96e.tar.gz is missing!]
5850
5851  internationalization changes and the fix to the documentation for strftime
5852
5853
5854Release code96d-data96c - 1996-02-12 11:05:27 -0500
5855
5856  The "code" file simply updates Bob Kridle's electronic address.
5857
5858  The "data" file updates rules for Mexico.
5859
5860
5861Release data96b - 1996-01-27 15:44:42 -0500
5862
5863  Kiribati change
5864
5865
5866Release code96c - 1996-01-16 16:58:15 -0500
5867
5868  leap-year streamlining and binary-search changes
5869
5870  fix to newctime.3
5871
5872
5873Release code96b - 1996-01-10 20:42:39 -0500
5874
5875  fixes and enhancements from Paul Eggert, including code that
5876  emulates the behavior of recent versions of the SunOS "date"
5877  command.
5878
5879
5880Release 96a - 1996-01-06 09:08:24 -0500
5881
5882  Israel updates
5883
5884  fixes to strftime.c for correct ISO 8601 week number generation,
5885  plus support for two new formats ('G' and 'g') to give ISO 8601 year
5886  numbers (which are not necessarily the same as calendar year numbers)
5887
5888
5889Release code95i-data95m - 1995-12-21 12:46:47 -0500
5890
5891  The latest revisions from Paul Eggert are included, the usno1995
5892  file has been updated, and a new file ("WWW") covering useful URLs
5893  has been added.
5894
5895
5896Release code95h-data95l - 1995-12-19 18:10:12 -0500
5897
5898  A simplification of a macro definition, a change to data for Sudan,
5899  and (for last minute shoppers) notes in the "Music" file on the CD
5900  "Old Man Time".
5901
5902
5903Release code95g-data95k - 1995-10-30 10:32:47 -0500
5904
5905  (slightly reformatted) 8-bit-clean proposed patch
5906
5907  minor patch: US/Eastern -> America/New_York
5908
5909  snapshot of the USNO's latest data ("usno1995")
5910
5911  some other minor cleanups
5912
5913
5914Release code95f-data95j - 1995-10-28 21:01:34 -0000
5915  [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
5916
5917  European cleanups
5918
5919  support for 64-bit time_t's
5920
5921  optimization in localtime.c
5922
5923
5924Release code95e - 1995-10-13 13:23:57 -0400
5925
5926  the mktime change to scan from future to past when trying to find time zone
5927  offsets
5928
5929
5930Release data95i - 1995-09-26 10:43:26 -0400
5931
5932  For Canada/Central, guess that the Sun customer's "one week too
5933  early" was just a approximation, and the true error is one month
5934  too early.  This is consistent with the rest of Canada.
5935
5936
5937Release data95h - 1995-09-21 11:26:48 -0400
5938
5939  latest changes from Paul Eggert
5940
5941
5942Release code95d - 1995-09-14 11:14:45 -0400
5943
5944  the addition of a "Music" file, which documents four recorded
5945  versions of the tune "Save That Time".
5946
5947
5948Release data95g - 1995-09-01 17:21:36 -0400
5949
5950  "yearistype" correction
5951
5952
5953Release data95f - 1995-08-28 20:46:56 -0400
5954
5955  Paul Eggert's change to the australasia file
5956
5957
5958Release data95e - 1995-07-08 18:02:34 -0400
5959
5960  The only change is a leap second at the end of this year.
5961  Thanks to Bradley White for forwarding news on the leap second.
5962
5963
5964Release data95d - 1995-07-03 13:26:22 -0400
5965
5966  Paul Eggert's changes
5967
5968
5969Release data95c - 1995-07-02 19:19:28 -0400
5970
5971  changes to "asia", "backward", "europe", and "southamerica"
5972  (read: northamericacentrics need not apply)
5973
5974
5975Release code95c - 1995-03-13 14:00:46 -0500
5976
5977  one-line fix for sign extension problems in detzcode
5978
5979
5980Release 95b - 1995-03-04 11:22:38 -0500
5981
5982  Minor changes in both:
5983
5984  The "code" file contains a workaround for the lack of "unistd.h" in
5985  Microsoft C++ version 7.
5986
5987  The "data" file contains a fixed "Link" for America/Shiprock.
5988
5989
5990Release 94h - 1994-12-10 12:51:14 -0500
5991
5992  The files:
5993
5994  *	incorporate the changes to "zdump" and "date" to make changes to
5995	the "TZ" environment variable permanent;
5996
5997  *	incorporate the table changes by Paul Eggert;
5998
5999  *	include (and document) support for universal time specifications in
6000	data files - but do not (yet) include use of this feature in the
6001	data files.
6002
6003  Think of this as "TZ Classic" - the software has been set up not to break if
6004  universal time shows up in its input, and data entries have been
6005  left as is so as not to break existing implementations.
6006
6007
6008Release data94f - 1994-08-20 12:56:09 -0400
6009
6010  (with thanks!) the latest data updates from Paul Eggert
6011
6012
6013Release data94e - 1994-06-04 13:13:53 -0400
6014
6015  [not summarized]
6016
6017
6018Release code94g - 1994-05-05 12:14:07 -0400
6019
6020  fix missing "optind.c" and a reference to it in the Makefile
6021
6022
6023Release code94f - 1994-05-05 13:00:33 -0000
6024  [tzcode94f.tar.gz is missing!]
6025
6026  changes to avoid overflow in difftime, as well as changes to cope
6027  with the 52/53 challenge in strftime
6028
6029
6030Release code94e - 1994-03-30 23:32:59 -0500
6031
6032  change for the benefit of PCTS
6033
6034
6035Release 94d - 1994-02-24 15:42:25 -0500
6036
6037  Avoid clashes with POSIX semantics for zones such as GMT+4.
6038
6039  Some other very minor housekeeping is also present.
6040
6041
6042Release code94c - 1994-02-10 08:52:40 -0500
6043
6044  Fix bug where mkdirs was broken unless you compile with
6045  -fwritable-strings (which is generally losing to do).
6046
6047
6048Release 94b - 1994-02-07 10:04:33 -0500
6049
6050  work by Paul Eggert who notes:
6051
6052  I found another book of time zone histories by E W Whitman; it's not
6053  as extensive as Shanks but has a few goodies of its own.  I used it
6054  to update the tables.  I also fixed some more as a result of
6055  correspondence with Adam David and Peter Ilieve, and move some stray
6056  links from 'europe' to 'backward'.  I corrected some scanning errors
6057  in usno1989.
6058
6059  As far as the code goes, I fixed zic to allow years in the range
6060  INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
6061  And I cleaned up the zic documentation a little bit.
6062
6063
6064Release data94a - 1994-02-03 08:58:54 -0500
6065
6066  It simply incorporates the recently announced leap second into the
6067  "leapseconds" file.
6068
6069
6070Release 93g - 1993-11-22 17:28:27 -0500
6071
6072  Paul Eggert has provided a good deal of historic information (based
6073  on Shanks), and there are some code changes to deal with the buglets
6074  that crawled out in dealing with the new information.
6075
6076
6077Release 93f - 1993-10-15 12:27:46 -0400
6078
6079  Paul Eggert's changes
6080
6081
6082Release 93e - 1993-09-05 21:21:44 -0400
6083
6084  This has updated data for Israel, England, and Kwajalein.  There's
6085  also an update to "zdump" to cope with Kwajalein's 24-hour jump.
6086  Thanks to Paul Eggert and Peter Ilieve for the changes.
6087
6088
6089Release 93d - 1993-06-17 23:34:17 -0400
6090
6091  new fix and new data on Israel
6092
6093
6094Release 93c - 1993-06-06 19:31:55 -0400
6095
6096  [not summarized]
6097
6098
6099Release 93b - 1993-02-02 14:53:58 -0500
6100
6101  updated "leapseconds" file
6102
6103
6104Release 93 - 1993-01-08 07:01:06 -0500
6105
6106  At kre's suggestion, the package has been split in two - a code piece
6107  (which also includes documentation) that's only of use to folks who
6108  want to recompile things and a data piece useful to anyone who can
6109  run "zic".
6110
6111  The new version has a few changes to the data files, a few
6112  portability changes, and an off-by-one fix (with thanks to
6113  Tom Karzes at deshaw.com for providing a description and a
6114  solution).
6115
6116
6117Release 92c - 1992-11-21 17:35:36 -0000
6118  [tz92c.tar.Z is missing!]
6119
6120  The fallout from the latest round of DST transitions.
6121
6122  There are changes for Portugal, Saskatchewan, and "Pacific-New";
6123  there's also a change to "zic.c" that makes it portable to more systems.
6124
6125
6126Release 92 - 1992-04-25 18:17:03 -0000
6127  [tz92.tar.Z is missing!]
6128
6129  By popular demand (well, at any rate, following a request by kre at munnari)
6130
6131
6132The 1989 update of the time zone package featured:
6133
6134  *	POSIXization (including interpretation of POSIX-style TZ environment
6135	variables, provided by Guy Harris),
6136  *	ANSIfication (including versions of "mktime" and "difftime"),
6137  *	SVIDulation (an "altzone" variable)
6138  *	MACHination (the "gtime" function)
6139  *	corrections to some time zone data (including corrections to the rules
6140	for Great Britain and New Zealand)
6141  *	reference data from the United States Naval Observatory for folks who
6142	want to do additional time zones
6143  *	and the 1989 data for Saudi Arabia.
6144
6145  (Since this code will be treated as "part of the implementation" in some
6146  places and as "part of the application" in others, there's no good way to
6147  name functions, such as timegm, that are not part of the proposed ANSI C
6148  standard; such functions have kept their old, underscore-free names in this
6149  update.)
6150
6151  And the "dysize" function has disappeared; it was present to allow
6152  compilation of the "date" command on old BSD systems, and a version of "date"
6153  is now provided in the package.  The "date" command is not created when you
6154  "make all" since it may lack options provided by the version distributed with
6155  your operating system, or may not interact with the system in the same way
6156  the native version does.
6157
6158  Since POSIX frowns on correct leap second handling, the default behavior of
6159  the "zic" command (in the absence of a "-L" option) has been changed to omit
6160  leap second information from its output files.
6161
6162
6163-----
6164Notes
6165
6166This file contains copies of the part of each release announcement
6167that talks about the changes in that release.  The text has been
6168adapted and reformatted for the purposes of this file.
6169
6170Traditionally a release R consists of a pair of tarball files,
6171tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
6172code2010a, data2012c) consist of just one or the other tarball, and a
6173few (e.g., code2012c-data2012d) have tarballs with mixed version
6174numbers.  Recent releases also come in an experimental format
6175consisting of a single tarball tzdb-R.tar.lz with extra data.
6176
6177Release timestamps are taken from the release's commit (for newer,
6178Git-based releases), from the newest file in the tarball (for older
6179releases, where this info is available) or from the email announcing
6180the release (if all else fails; these are marked with a time zone
6181abbreviation of -0000 and an "is missing!" comment).
6182
6183Earlier versions of the code and data were not announced on the tz
6184list and are not summarized here.
6185
6186This file is in the public domain.
6187
6188Local Variables:
6189coding: utf-8
6190End:
6191