xref: /freebsd/contrib/tzdata/NEWS (revision d5b0e70f7e04d971691517ce1304d86a1e367e2e)
1News for the tz database
2
3Release 2022f - 2022-10-28 18:04:57 -0700
4
5  Briefly:
6    Mexico will no longer observe DST except near the US border.
7    Chihuahua moves to year-round -06 on 2022-10-30.
8    Fiji no longer observes DST.
9    Move links to 'backward'.
10    In vanguard form, GMT is now a Zone and Etc/GMT a link.
11    zic now supports links to links, and vanguard form uses this.
12    Simplify four Ontario zones.
13    Fix a Y2438 bug when reading TZif data.
14    Enable 64-bit time_t on 32-bit glibc platforms.
15    Omit large-file support when no longer needed.
16    In C code, use some C23 features if available.
17    Remove no-longer-needed workaround for Qt bug 53071.
18
19  Changes to future timestamps.
20
21    Mexico will no longer observe DST after 2022, except for areas
22    near the US border that continue to observe US DST rules.
23    On 2022-10-30 at 02:00 the Mexican state of Chihuahua moves
24    from -07 (-06 with DST) to year-round -06, thus not changing
25    its clocks that day.  The new law states that Chihuahua
26    near the US border no longer observes US DST.
27
28    Fiji will not observe DST in 2022/3.  (Thanks to Shalvin Narayan.)
29    For now, assume DST is suspended indefinitely.
30
31  Changes to data
32
33    Move links to 'backward' to ease and simplify link maintenance.
34    This affects generated data only if you use 'make BACKWARD='.
35
36    GMT is now a Zone and Etc/GMT a link instead of vice versa,
37    as GMT is needed for leap second support whereas Etc/GMT is not.
38    However, this change exposes a bug in TZUpdater 2.3.2 so it is
39    present only in vanguard form for now.
40
41    Vanguard form now uses links to links, as zic now supports this.
42
43  Changes to past timestamps
44
45    Simplify four Ontario zones, as most of the post-1970 differences
46    seem to have been imaginary.  (Problem reported by Chris Walton.)
47    Move America/Nipigon, America/Rainy_River, and America/Thunder_Bay
48    to 'backzone'; backward-compatibility links still work, albeit
49    with some different timestamps before November 2005.
50
51  Changes to code
52
53    zic now supports links to links regardless of input line order.
54    For example, if Australia/Sydney is a Zone, the lines
55      Link Australia/Canberra Australia/ACT
56      Link Australia/Sydney Australia/Canberra
57    now work correctly, even though the shell commands
58      ln Australia/Canberra Australia/ACT
59      ln Australia/Sydney Australia/Canberra
60    would fail because the first command attempts to use a link
61    Australia/Canberra that does not exist until after the second
62    command is executed.  Previously, zic had unspecified behavior if
63    a Link line's target was another link, and zic often misbehaved if
64    a Link line's target was a later Link line.
65
66    Fix line number in zic's diagnostic for a link to a link.
67
68    Fix a bug that caused localtime to mishandle timestamps starting
69    in the year 2438 when reading data generated by 'zic -b fat' when
70    distant-future DST transitions occur at times given in standard
71    time or in UT, not the usual case of local time.  This occurs when
72    the corresponding .zi Rule lines specify DST transitions with TO
73    columns of 'max' and AT columns that end in 's' or 'u'.  The
74    number 2438 comes from the 32-bit limit in the year 2038, plus the
75    400-year Gregorian cycle.  (Problem reported by Bradley White.)
76
77    On glibc 2.34 and later, which optionally supports 64-bit time_t
78    on platforms like x86 where time_t was traditionally 32 bits,
79    default time_t to 64 instead of 32 bits.  This lets functions like
80    localtime support timestamps after the year 2038, and fixes
81    year-2038 problems in zic when accessing files dated after 2038.
82    To continue to limit time_t to 32 bits on these platforms, use
83    "make CFLAGS='-D_TIME_BITS=32'".
84
85    In C code, do not enable large-file support on platforms like AIX
86    and macOS that no longer need it now that tzcode does not use
87    off_t or related functions like 'stat'.  Large-file support is
88    still enabled by default on GNU/Linux, as it is needed for 64-bit
89    time_t support.
90
91    In C code, prefer C23 keywords to pre-C23 macros for alignof,
92    bool, false, and true.  Also, use the following C23 features if
93    available: __has_include, unreachable.
94
95    zic no longer works around Qt bug 53071, as the relevant Qt
96    releases have been out of support since 2019.  This change affects
97    only fat TZif files, as thin files never had the workaround.
98
99    zdump no longer modifies the environ vector when compiled on
100    platforms lacking tm_zone or when compiled with -DUSE_LTZ=0.
101    This avoid undefined behavior on POSIX platforms.
102
103
104Release 2022e - 2022-10-11 11:13:02 -0700
105
106  Briefly:
107    Jordan and Syria switch from +02/+03 with DST to year-round +03.
108
109  Changes to future timestamps
110
111    Jordan and Syria are abandoning the DST regime and are changing to
112    permanent +03, so they will not fall back from +03 to +02 on
113    2022-10-28.  (Thanks to Steffen Thorsen and Issam Al-Zuwairi.)
114
115  Changes to past timestamps
116
117    On 1922-01-01 Tijuana adopted standard time at 00:00, not 01:00.
118
119  Changes to past time zone abbreviations and DST flags
120
121    The temporary advancement of clocks in central Mexico in summer
122    1931 is now treated as daylight saving time, instead of as two
123    changes to standard time.
124
125
126Release 2022d - 2022-09-23 12:02:57 -0700
127
128  Briefly:
129    Palestine transitions are now Saturdays at 02:00.
130    Simplify three Ukraine zones into one.
131
132  Changes to future timestamps
133
134    Palestine now springs forward and falls back at 02:00 on the
135    first Saturday on or after March 24 and October 24, respectively.
136    This means 2022 falls back 10-29 at 02:00, not 10-28 at 01:00.
137    (Thanks to Heba Hamad.)
138
139  Changes to past timestamps
140
141    Simplify three Ukraine zones to one, since the post-1970
142    differences seem to have been imaginary.  Move Europe/Uzhgorod and
143    Europe/Zaporozhye to 'backzone'; backward-compatibility links
144    still work, albeit with different timestamps before October 1991.
145
146
147Release 2022c - 2022-08-15 17:47:18 -0700
148
149  Briefly:
150    Work around awk bug in FreeBSD, macOS, etc.
151    Improve tzselect on intercontinental Zones.
152
153  Changes to code
154
155    Work around a bug in onetrueawk that broke commands like
156    'make traditional_tarballs' on FreeBSD, macOS, etc.
157    (Problem reported by Deborah Goldsmith.)
158
159    Add code to tzselect that uses experimental structured comments in
160    zone1970.tab to clarify whether Zones like Africa/Abidjan and
161    Europe/Istanbul cross continent or ocean boundaries.
162    (Inspired by a problem reported by Peter Krefting.)
163
164    Fix bug with 'zic -d /a/b/c' when /a is unwritable but the
165    directory /a/b already exists.
166
167    Remove zoneinfo2tdf.pl, as it was unused and triggered false
168    malware alarms on some email servers.
169
170
171Release 2022b - 2022-08-10 15:38:32 -0700
172
173  Briefly:
174    Chile's DST is delayed by a week in September 2022.
175    Iran no longer observes DST after 2022.
176    Rename Europe/Kiev to Europe/Kyiv.
177    New zic -R option
178    Vanguard form now uses %z.
179    Finish moving duplicate-since-1970 zones to 'backzone'.
180    New build option PACKRATLIST
181    New tailored_tarballs target, replacing rearguard_tarballs
182
183  Changes to future timestamps
184
185    Chile's 2022 DST start is delayed from September 4 to September 11.
186    (Thanks to Juan Correa.)
187
188    Iran plans to stop observing DST permanently, after it falls back
189    on 2022-09-21.  (Thanks to Ali Mirjamali.)
190
191  Changes to past timestamps
192
193    Finish moving to 'backzone' the location-based zones whose
194    timestamps since 1970 are duplicates; adjust links accordingly.
195    This change ordinarily affects only pre-1970 timestamps, and with
196    the new PACKRATLIST option it does not affect any timestamps.
197    In this round the affected zones are Antarctica/Vostok,
198    Asia/Brunei, Asia/Kuala_Lumpur, Atlantic/Reykjavik,
199    Europe/Amsterdam, Europe/Copenhagen, Europe/Luxembourg,
200    Europe/Monaco, Europe/Oslo, Europe/Stockholm, Indian/Christmas,
201    Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Reunion,
202    Pacific/Chuuk, Pacific/Funafuti, Pacific/Majuro, Pacific/Pohnpei,
203    Pacific/Wake and Pacific/Wallis, and the affected links are
204    Arctic/Longyearbyen, Atlantic/Jan_Mayen, Iceland, Pacific/Ponape,
205    Pacific/Truk, and Pacific/Yap.
206
207    From fall 1994 through fall 1995, Shanks wrote that Crimea's
208    DST transitions were at 02:00 standard time, not at 00:00.
209    (Thanks to Michael Deckers.)
210
211    Iran adopted standard time in 1935, not 1946.  In 1977 it observed
212    DST from 03-21 23:00 to 10-20 24:00; its 1978 transitions were on
213    03-24 and 08-05, not 03-20 and 10-20; and its spring 1979
214    transition was on 05-27, not 03-21.
215    (Thanks to Roozbeh Pournader and Francis Santoni.)
216
217    Chile's observance of -04 from 1946-08-29 through 1947-03-31 was
218    considered DST, not standard time.  Santiago and environs had moved
219    their clocks back to rejoin the rest of mainland Chile; put this
220    change at the end of 1946-08-28.  (Thanks to Michael Deckers.)
221
222    Some old, small clock transitions have been removed, as people at
223    the time did not change their clocks.  This affects Asia/Hong_Kong
224    in 1904, Asia/Ho_Chi_Minh in 1906, and Europe/Dublin in 1880.
225
226  Changes to zone name
227
228    Rename Europe/Kiev to Europe/Kyiv, as "Kyiv" is more common in
229    English now.  Spelling of other names in Ukraine has not yet
230    demonstrably changed in common English practice so for now these
231    names retain old spellings, as in other countries (e.g.,
232    Europe/Prague not "Praha", and Europe/Sofia not "Sofiya").
233
234  Changes to code
235
236    zic has a new option '-R @N' to output explicit transitions < N.
237    (Need suggested by Almaz Mingaleev.)
238
239    'zic -r @N' no longer outputs bad data when N < first transition.
240    (Problem introduced in 2021d and reported by Peter Krefting.)
241
242    zic now checks its input for NUL bytes and unterminated lines, and
243    now supports input line lengths up to 2048 (not 512) bytes.
244
245    gmtime and related code now use the abbreviation "UTC" not "GMT".
246    POSIX is being revised to require this.
247
248    When tzset and related functions set vestigial static variables
249    like tzname, they now prefer specified timestamps to unspecified ones.
250    (Problem reported by Almaz Mingaleev.)
251
252    zic no longer complains "can't determine time zone abbreviation to
253    use just after until time" when a transition to a new standard
254    time occurs simultaneously with the first DST fallback transition.
255
256  Changes to build procedure
257
258    Source data in vanguard form now uses the %z notation, introduced
259    in release 2015f.  For example, for America/Sao_Paulo vanguard
260    form contains the zone continuation line "-3:00 Brazil %z", which
261    is simpler and more reliable than the line "-3:00 Brazil -03/-02"
262    used in main and rearguard forms.  The plan is for the main form
263    to use %z eventually; in the meantime maintainers of zi parsers
264    are encouraged to test the parsers on vanguard.zi.
265
266    The Makefile has a new PACKRATLIST option to select a subset of
267    'backzone'.  For example, 'make PACKRATDATA=backzone
268    PACKRATLIST=zone.tab' now generates TZif files identical to those
269    of the global-tz project.
270
271    The Makefile has a new tailored_tarballs target for generating
272    special-purpose tarballs.  It generalizes and replaces the
273    rearguard_tarballs target and related targets and macros, which
274    are now obsolescent.
275
276    'make install' now defaults LOCALTIME to Factory not GMT,
277    which means the default abbreviation is now "-00" not "GMT".
278
279    Remove the posix_packrat target, marked obsolescent in 2016a.
280
281
282Release 2022a - 2022-03-15 23:02:01 -0700
283
284  Briefly:
285    Palestine will spring forward on 2022-03-27, not -03-26.
286    zdump -v now outputs better failure indications.
287    Bug fixes for code that reads corrupted TZif data.
288
289  Changes to future timestamps
290
291    Palestine will spring forward on 2022-03-27, not 2022-03-26.
292    (Thanks to Heba Hamad.)  Predict future transitions for first
293    Sunday >= March 25.  Additionally, predict fallbacks to be the first
294    Friday on or after October 23, not October's last Friday, to be more
295    consistent with recent practice.  The first differing fallback
296    prediction is on 2025-10-24, not 2025-10-31.
297
298  Changes to past timestamps
299
300    From 1992 through spring 1996, Ukraine's DST transitions were at
301    02:00 standard time, not at 01:00 UTC.  (Thanks to Alois Treindl.)
302
303    Chile's Santiago Mean Time and its LMT precursor have been adjusted
304    eastward by 1 second to align with past and present law.
305
306  Changes to commentary
307
308    Add several references for Chile's 1946/1947 transitions, some of
309    which only affected portions of the country.
310
311  Changes to code
312
313    Fix bug when mktime gets confused by truncated TZif files with
314    unspecified local time.  (Problem reported by Almaz Mingaleev.)
315
316    Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
317    (Problem reported by Christos Zoulas.)
318
319    When reading a version 2 or later TZif file, the TZif reader now
320    validates the version 1 header and data block only enough to skip
321    over them, as recommended by RFC 8536 section 4.  Also, the TZif
322    reader no longer mistakenly attempts to parse a version 1 TZIf
323    file header as a TZ string.
324
325    zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
326    when local time and UT cannot be determined for a timestamp.
327
328  Changes to build procedure
329
330    Distribution tarballs now use standard POSIX.1-1988 ustar format
331    instead of GNU format.  Although the formats are almost identical
332    for these tarballs, ustar headers' magic fields contain "ustar"
333    instead of "ustar ", and their version fields contain "00" instead
334    of " ".  The two formats are planned to diverge more significantly
335    for tzdb releases after 2242-03-16 12:56:31 UTC, when the ustar
336    format becomes obsolete and the tarballs switch to pax format, an
337    extension of ustar.  For details about these formats, please see
338    "pax - portable archive interchange", IEEE Std 1003.1-2017,
339    <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13>.
340
341
342Release 2021e - 2021-10-21 18:41:00 -0700
343
344  Changes to future timestamps
345
346    Palestine will fall back 10-29 (not 10-30) at 01:00.
347    (Thanks to P Chan and Heba Hemad.)
348
349
350Release 2021d - 2021-10-15 13:48:18 -0700
351
352  Briefly:
353    Fiji suspends DST for the 2021/2022 season.
354    'zic -r' marks unspecified timestamps with "-00".
355
356  Changes to future timestamps
357
358    Fiji will suspend observance of DST for the 2021/2022 season.
359    Assume for now that it will return next year.  (Thanks to Jashneel
360    Kumar and P Chan.)
361
362  Changes to code
363
364    'zic -r' now uses "-00" time zone abbreviations for intervals
365    with UT offsets that are unspecified due to -r truncation.
366    This implements a change in draft Internet RFC 8536bis.
367
368
369Release 2021c - 2021-10-01 14:21:49 -0700
370
371  Briefly:
372    Revert most 2021b changes to 'backward'.
373    Fix 'zic -b fat' bug in pre-1970 32-bit data.
374    Fix two Link line typos.
375    Distribute SECURITY file.
376
377    This release is intended as a bugfix release, to fix compatibility
378    problems and typos reported since 2021b was released.
379
380  Changes to Link directives
381
382    Revert almost all of 2021b's changes to the 'backward' file,
383    by moving Link directives back to where they were in 2021a.
384    Although 'zic' doesn't care which source file contains a Link
385    directive, some downstream uses ran into trouble with the move.
386    (Problem reported by Stephen Colebourne for Joda-Time.)
387
388    Fix typo that linked Atlantic/Jan_Mayen to the wrong location
389    (problem reported by Chris Walton).
390
391    Fix 'backzone' typo that linked America/Virgin to the wrong
392    location (problem reported by Michael Deckers).
393
394  Changes to code
395
396    Fix a bug in 'zic -b fat' that caused old timestamps to be
397    mishandled in 32-bit-only readers (problem reported by Daniel
398    Fischer).
399
400  Changes to documentation
401
402    Distribute the SECURITY file (problem reported by Andreas Radke).
403
404
405Release 2021b - 2021-09-24 16:23:00 -0700
406
407  Briefly:
408    Jordan now starts DST on February's last Thursday.
409    Samoa no longer observes DST.
410    Merge more location-based Zones whose timestamps agree since 1970.
411    Move some backward-compatibility links to 'backward'.
412    Rename Pacific/Enderbury to Pacific/Kanton.
413    Correct many pre-1993 transitions in Malawi, Portugal, etc.
414    zic now creates each output file or link atomically.
415    zic -L no longer omits the POSIX TZ string in its output.
416    zic fixes for truncation and leap second table expiration.
417    zic now follows POSIX for TZ strings using all-year DST.
418    Fix some localtime crashes and bugs in obscure cases.
419    zdump -v now outputs more-useful boundary cases.
420    tzfile.5 better matches a draft successor to RFC 8536.
421    A new file SECURITY.
422
423    This release is prompted by recent announcements by Jordan and Samoa.
424    It incorporates many other changes that had accumulated since 2021a.
425    However, it omits most proposed changes that merged all Zones
426    agreeing since 1970, as concerns were raised about doing too many of
427    these changes at once.  It does keeps some of these changes in the
428    interest of making tzdb more equitable one step at a time; see
429    "Merge more location-based Zones" below.
430
431  Changes to future timestamps
432
433    Jordan now starts DST on February's last Thursday.
434    (Thanks to Steffen Thorsen.)
435
436    Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
437
438  Changes to zone name
439
440    Rename Pacific/Enderbury to Pacific/Kanton.  When we added
441    Enderbury in 1993, we did not know that it is uninhabited and that
442    Kanton (population two dozen) is the only inhabited location in
443    that timezone.  The old name is now a backward-compatibility link.
444
445  Changes to past timestamps
446
447    Correct many pre-1993 transitions, fixing entries originally
448    derived from Shanks, Whitman, and Mundell.  The fixes include:
449      - Barbados: standard time was introduced in 1911, not 1932; and
450	DST was observed in 1942-1944
451      - Cook Islands: In 1899 they switched from east to west of GMT,
452	celebrating Christmas for two days.  They (and Niue) switched
453	to standard time in 1952, not 1901.
454      - Guyana: corrected LMT for Georgetown; the introduction of
455	standard time in 1911, not 1915; and corrections to 1975 and
456	1992 transitions
457      - Kanton: uninhabited before 1937-08-31
458      - Niue: only observed -11:20 from 1952 through 1964, then went to
459        -11 instead of -11:30
460      - Portugal: DST was observed in 1950
461      - Tonga: corrected LMT; the introduction of standard time in 1945,
462        not 1901; and corrections to the transition from +12:20 to +13
463        in 1961, not 1941
464    Additional fixes to entries in the 'backzone' file include:
465      - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
466      - The Gambia: 1933 and 1942 transitions
467      - Malawi: several 1911 through 1925 transitions
468      - Sierra Leone: several 1913 through 1941 transitions, and DST
469	was NOT observed in 1957 through 1962
470    (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
471    Alois Treindl.)
472
473    Merge more location-based Zones whose timestamps agree since 1970,
474    as pre-1970 timestamps are out of scope.  This is part of a
475    process that has been ongoing since 2013.  This does not affect
476    post-1970 timestamps, and timezone historians who build with 'make
477    PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
478    When merging, keep the most-populous location's data, and move
479    data for other locations to 'backzone' with a backward
480    link in 'backward'.  For example, move America/Creston data to
481    'backzone' with a link in 'backward' from America/Phoenix because
482    the two timezones' timestamps agree since 1970; this change
483    affects some pre-1968 timestamps in America/Creston because
484    Creston and Phoenix disagreed before 1968.  The affected Zones
485    are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
486    America/Creston, America/Curacao, America/Nassau,
487    America/Port_of_Spain, Antarctica/DumontDUrville, and
488    Antarctica/Syowa.
489
490  Changes to maintenance procedure
491
492    The new file SECURITY covers how to report security-related bugs.
493
494    Several backward-compatibility links have been moved to the
495    'backward' file.  These links, which range from Africa/Addis_Ababa
496    to Pacific/Saipan, are only for compatibility with now-obsolete
497    guidelines suggesting an entry for every ISO 3166 code.
498    The intercontinental convenience links Asia/Istanbul and
499    Europe/Nicosia have also been moved to 'backward'.
500
501  Changes to code
502
503    zic now creates each output file or link atomically,
504    possibly by creating a temporary file and then renaming it.
505    This avoids races where a TZ setting would temporarily stop
506    working while zic was installing a replacement file or link.
507
508    zic -L no longer omits the POSIX TZ string in its output.
509    Starting with 2020a, zic -L truncated its output according to the
510    "Expires" directive or "#expires" comment in the leapseconds file.
511    The resulting TZif files omitted daylight saving transitions after
512    the leap second table expired, which led to far less-accurate
513    predictions of times after the expiry.  Although future timestamps
514    cannot be converted accurately in the presence of leap seconds, it
515    is more accurate to convert near-future timestamps with a few
516    seconds error than with an hour error, so zic -L no longer
517    truncates output in this way.
518
519    Instead, when zic -L is given the "Expires" directive, it now
520    outputs the expiration by appending a no-change entry to the leap
521    second table.  Although this should work well with most TZif
522    readers, it does not conform to Internet RFC 8536 and some pickier
523    clients (including tzdb 2017c through 2021a) reject it, so
524    "Expires" directives are currently disabled by default.  To enable
525    them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
526    this new feature it is marked with a new TZif version number 4,
527    a format intended to be documented in a successor to RFC 8536.
528
529    zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
530    that omits leap second information for the range LO..B when LO
531    falls between two leap seconds A and B.  Instead, it generates a
532    TZif version 4 file that represents the previously-missing
533    information.
534
535    The TZif reader now allows the leap second table to begin with a
536    correction other than -1 or +1, and to contain adjacent
537    transitions with equal corrections.  This supports TZif version 4.
538
539    The TZif reader now lets leap seconds occur less than 28 days
540    apart.  This supports possible future TZif extensions.
541
542    Fix bug that caused 'localtime' etc. to crash when TZ was
543    set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
544    not conform to POSIX but does conform to Internet RFC 8536.
545
546    Fix another bug that caused 'localtime' etc. to crash when TZ was
547    set to a POSIX-conforming but unusual TZ string like
548    "EST5EDT4,0/0,J365/0", where almost all the year is DST.
549
550    Fix yet another bug that caused 'localtime' etc. to mishandle slim
551    TZif files containing leap seconds after the last explicit
552    transition in the table, or when handling far-future timestamps
553    in slim TZif files lacking leap seconds.
554
555    Fix localtime misbehavior involving positive leap seconds.
556    This change affects only behavior for "right" system time,
557    which contains leap seconds, and only if the UT offset is
558    not a multiple of 60 seconds when a positive leap second occurs.
559    (No such timezone exists in tzdb, luckily.)  Without the fix,
560    the timestamp was ambiguous during a positive leap second.
561    With the fix, any seconds occurring after a positive leap second
562    and within the same localtime minute are counted through 60, not
563    through 59; their UT offset (tm_gmtoff) is the same as before.
564    Here is how the fix affects timestamps in a timezone with UT
565    offset +01:23:45 (5025 seconds) and with a positive leap second at
566    1972-06-30 23:59:60 UTC (78796800):
567
568	time_t    without the fix      with the fix
569	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
570	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
571	...
572	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
573	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
574
575    Fix an unlikely bug that caused 'localtime' etc. to misbehave if
576    civil time changes a few seconds before time_t wraps around, when
577    leap seconds are enabled.
578
579    Fix bug in zic -r; in some cases, the dummy time type after the
580    last time transition disagreed with the TZ string, contrary to
581    Internet RFC 8563 section 3.3.
582
583    Fix a bug with 'zic -r @X' when X is a negative leap second that
584    has a nonnegative correction.  Without the fix, the output file
585    was truncated so that X appeared to be a positive leap second.
586    Fix a similar, even-less-likely bug when truncating at a positive
587    leap second that has a nonpositive correction.
588
589    zic -r now reports an error if given rolling leap seconds, as this
590    usage has never generally worked and is evidently unused.
591
592    zic now generates a POSIX-conforming TZ string for TZif files
593    where all-year DST is predicted for the indefinite future.
594    For example, for all-year Eastern Daylight Time, zic now generates
595    "XXX3EDT4,0/0,J365/23" where it previously generated
596    "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
597    noting the possibility of POSIX conformance.)
598
599    zic.c no longer requires sys/wait.h (thanks to spazmodius for
600    noting it wasn't needed).
601
602    When reading slim TZif files, zdump no longer mishandles leap
603    seconds on the rare platforms where time_t counts leap seconds,
604    fixing a bug introduced in 2014g.
605
606    zdump -v now outputs timestamps at boundaries of what localtime
607    and gmtime can represent, instead of the less-useful timestamps
608    one day after the minimum and one day before the maximum.
609    (Thanks to Arthur David Olson for prototype code, and to Manuela
610    Friedrich for debugging help.)
611
612    zdump's -c and -t options are now consistently inclusive for the
613    lower time bound and exclusive for the upper.  Formerly they were
614    inconsistent.  (Confusion noted by Martin Burnicki.)
615
616  Changes to build procedure
617
618    You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
619    non-POSIX hosts where malloc doesn't set errno.
620    (Problem reported by Jan Engelhardt.)
621
622  Changes to documentation
623
624    tzfile.5 better matches a draft successor to RFC 8536
625    <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.
626
627
628Release 2021a - 2021-01-24 10:54:57 -0800
629
630  Changes to future timestamps
631
632    South Sudan changes from +03 to +02 on 2021-02-01 at 00:00.
633    (Thanks to Steffen Thorsen.)
634
635
636Release 2020f - 2020-12-29 00:17:46 -0800
637
638  Change to build procedure
639
640    'make rearguard_tarballs' no longer generates a bad rearguard.zi,
641    fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
642
643
644Release 2020e - 2020-12-22 15:14:34 -0800
645
646  Briefly:
647    Volgograd switches to Moscow time on 2020-12-27 at 02:00.
648
649  Changes to future timestamps
650
651    Volgograd changes time zone from +04 to +03 on 2020-12-27 at 02:00.
652    (Thanks to Alexander Krivenyshev and Stepan Golosunov.)
653
654  Changes to past timestamps
655
656    Correct many pre-1986 transitions, fixing entries originally
657    derived from Shanks.  The fixes include:
658      - Australia: several 1917 through 1971 transitions
659      - The Bahamas: several 1941 through 1945 transitions
660      - Bermuda: several 1917 through 1956 transitions
661      - Belize: several 1942 through 1968 transitions
662      - Ghana: several 1915 through 1956 transitions
663      - Israel and Palestine: several 1940 through 1985 transitions
664      - Kenya and adjacent: several 1908 through 1960 transitions
665      - Nigeria and adjacent: correcting LMT in Lagos, and several 1905
666        through 1919 transitions
667      - Seychelles: the introduction of standard time in 1907, not 1906
668      - Vanuatu: DST in 1973-1974, and a corrected 1984 transition
669    (Thanks to P Chan.)
670
671    Because of the Australia change, Australia/Currie (King Island) is
672    no longer needed, as it is identical to Australia/Hobart for all
673    timestamps since 1970 and was therefore created by mistake.
674    Australia/Currie has been moved to the 'backward' file and its
675    corrected data moved to the 'backzone' file.
676
677  Changes to past time zone abbreviations and DST flags
678
679    To better match legislation in Turks and Caicos, the 2015 shift to
680    year-round observance of -04 is now modeled as AST throughout before
681    returning to Eastern Time with US DST in 2018, rather than as
682    maintaining EDT until 2015-11-01.  (Thanks to P Chan.)
683
684  Changes to documentation
685
686    The zic man page now documents zic's coalescing of transitions
687    when a zone falls back just before DST springs forward.
688
689
690Release 2020d - 2020-10-21 11:24:13 -0700
691
692  Briefly:
693    Palestine ends DST earlier than predicted, on 2020-10-24.
694
695  Changes to past and future timestamps
696
697    Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
698    as previously predicted (thanks to Sharef Mustafa.)  Its
699    2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
700    Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
701    its spring 2020 transition was on March 28 at 00:00, not March 27
702    (thanks to Pierre Cashon.)  This affects Asia/Gaza and
703    Asia/Hebron.  Assume future spring and fall transitions will be on
704    the Saturday preceding the last Sunday of March and October,
705    respectively.
706
707
708Release 2020c - 2020-10-16 11:15:53 -0700
709
710  Briefly:
711    Fiji starts DST later than usual, on 2020-12-20.
712
713  Changes to future timestamps
714
715    Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
716    previously predicted.  DST will still end on 2021-01-17.
717    (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
718    the later-than-usual start date is a one-time departure from the
719    recent pattern.
720
721  Changes to build procedure
722
723    Rearguard tarballs now contain an empty file pacificnew.
724    Some older downstream software expects this file to exist.
725    (Problem reported by Mike Cullinan.)
726
727
728Release 2020b - 2020-10-06 18:35:04 -0700
729
730  Briefly:
731    Revised predictions for Morocco's changes starting in 2023.
732    Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
733    Macquarie Island has stayed in sync with Tasmania since 2011.
734    Casey, Antarctica is at +08 in winter and +11 in summer.
735    zic no longer supports -y, nor the TYPE field of Rules.
736
737  Changes to future timestamps
738
739    Morocco's spring-forward after Ramadan is now predicted to occur
740    no sooner than two days after Ramadan, instead of one day.
741    (Thanks to Milamber.)  The first altered prediction is for 2023,
742    now predicted to spring-forward on April 30 instead of April 23.
743
744  Changes to past and future timestamps
745
746   Casey Station, Antarctica has been using +08 in winter and +11 in
747   summer since 2018.  The most recent transition from +08 to +11 was
748   2020-10-04 00:01.  Also, Macquarie Island has been staying in
749   sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
750
751  Changes to past and future time zone abbreviations and DST flags
752
753    Canada's Yukon, represented by America/Whitehorse and
754    America/Dawson, changes its time zone rules from -08/-07 to
755    permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
756    This change affects only the time zone abbreviation (MST vs PDT)
757    and daylight saving flag for the period between the two dates.
758    (Thanks to Andrew G. Smith.)
759
760  Changes to past timestamps
761
762    Correct several transitions for Hungary for 1918/1983.
763    For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
764    (Thanks to Géza Nyáry.)  Also, the 1890 transition to standard
765    time was on 11-01, not 10-01 (thanks to Michael Deckers).
766
767    The 1891 French transition was on March 16, not March 15.  The
768    1911-03-11 French transition was at midnight, not a minute later.
769    Monaco's transitions were on 1892-06-01 and 1911-03-29, not
770    1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
771
772  Changes to code
773
774    Support for zic's long-obsolete '-y YEARISTYPE' option has been
775    removed and, with it, so has support for the TYPE field in Rule
776    lines, which is now reserved for compatibility with earlier zic.
777    These features were previously deprecated in release 2015f.
778    (Thanks to Tim Parenti.)
779
780    zic now defaults to '-b slim' instead of to '-b fat'.
781
782    zic's new '-l -' and '-p -' options uninstall any existing
783    localtime and posixrules files, respectively.
784
785    The undocumented and ineffective tzsetwall function has been
786    removed.
787
788  Changes to build procedure
789
790    The Makefile now defaults POSIXRULES to '-', so the posixrules
791    feature (obsolete as of 2019b) is no longer installed by default.
792
793  Changes to documentation and commentary
794
795    The long-obsolete files pacificnew, systemv, and yearistype.sh have
796    been removed from the distribution.  (Thanks to Tim Parenti.)
797
798
799Release 2020a - 2020-04-23 16:03:47 -0700
800
801  Briefly:
802    Morocco springs forward on 2020-05-31, not 2020-05-24.
803    Canada's Yukon advanced to -07 year-round on 2020-03-08.
804    America/Nuuk renamed from America/Godthab.
805    zic now supports expiration dates for leap second lists.
806
807  Changes to future timestamps
808
809    Morocco's second spring-forward transition in 2020 will be May 31,
810    not May 24 as predicted earlier.  (Thanks to Semlali Naoufal.)
811    Adjust future-year predictions to use the first Sunday after the
812    day after Ramadan, not the first Sunday after Ramadan.
813
814    Canada's Yukon, represented by America/Whitehorse and
815    America/Dawson, advanced to -07 year-round, beginning with its
816    spring-forward transition on 2020-03-08, and will not fall back on
817    2020-11-01.  Although a government press release calls this
818    "permanent Pacific Daylight Saving Time", we prefer MST for
819    consistency with nearby Dawson Creek, Creston, and Fort Nelson.
820    (Thanks to Tim Parenti.)
821
822  Changes to past timestamps
823
824    Shanghai observed DST in 1919.  (Thanks to Phake Nick.)
825
826  Changes to timezone identifiers
827
828    To reflect current usage in English better, America/Godthab has
829    been renamed to America/Nuuk.  A backwards-compatibility link
830    remains for the old name.
831
832  Changes to code
833
834    localtime.c no longer mishandles timestamps after the last
835    transition in a TZif file with leap seconds and with daylight
836    saving time transitions projected into the indefinite future.
837    For example, with TZ='America/Los_Angeles' with leap seconds,
838    zdump formerly reported a DST transition on 2038-03-14
839    from 01:59:32.999... to 02:59:33 instead of the correct transition
840    from 01:59:59.999... to 03:00:00.
841
842    zic -L now supports an Expires line in the leapseconds file, and
843    truncates the TZif output accordingly.  This propagates leap
844    second expiration information into the TZif file, and avoids the
845    abovementioned localtime.c bug as well as similar bugs present in
846    many client implementations.  If no Expires line is present, zic
847    -L instead truncates the TZif output based on the #expires comment
848    present in leapseconds files distributed by tzdb 2018f and later;
849    however, this usage is obsolescent.  For now, the distributed
850    leapseconds file has an Expires line that is commented out, so
851    that the file can be fed to older versions of zic which ignore the
852    commented-out line.  Future tzdb distributions are planned to
853    contain a leapseconds file with an Expires line.
854
855    The configuration macros HAVE_TZNAME and USG_COMPAT should now be
856    set to 1 if the system library supports the feature, and 2 if not.
857    As before, these macros are nonzero if tzcode should support the
858    feature, zero otherwise.
859
860    The configuration macro ALTZONE now has the same values with the
861    same meaning as HAVE_TZNAME and USG_COMPAT.
862
863    The code's defense against CRLF in leap-seconds.list is now
864    portable to POSIX awk.  (Problem reported by Deborah Goldsmith.)
865
866    Although the undocumented tzsetwall function is not changed in
867    this release, it is now deprecated in preparation for removal in
868    future releases.  Due to POSIX requirements, tzsetwall has not
869    worked for some time.  Any code that uses it should instead use
870    tzalloc(NULL) or, if portability trumps thread-safety, should
871    unset the TZ environment variable.
872
873  Changes to commentary
874
875    The Îles-de-la-Madeleine and the Listuguj reserve are noted as
876    following America/Halifax, and comments about Yukon's "south" and
877    "north" have been corrected to say "east" and "west".  (Thanks to
878    Jeffery Nichols.)
879
880
881Release 2019c - 2019-09-11 08:59:48 -0700
882
883  Briefly:
884    Fiji observes DST from 2019-11-10 to 2020-01-12.
885    Norfolk Island starts observing Australian-style DST.
886
887  Changes to future timestamps
888
889    Fiji's next DST transitions will be 2019-11-10 and 2020-01-12
890    instead of 2019-11-03 and 2020-01-19.  (Thanks to Raymond Kumar.)
891    Adjust future guesses accordingly.
892
893    Norfolk Island will observe Australian-style DST starting in
894    spring 2019.  The first transition is on 2019-10-06.  (Thanks to
895    Kyle Czech and Michael Deckers.)
896
897  Changes to past timestamps
898
899    Many corrections to time in Turkey from 1940 through 1985.
900    (Thanks to Oya Vulaş via Alois Treindl, and to Kıvanç Yazan.)
901
902    The Norfolk Island 1975-03-02 transition was at 02:00 standard
903    time, not 02:00 DST.  (Thanks to Michael Deckers.)
904
905    South Korea observed DST from 1948 through 1951.  Although this
906    info was supposed to appear in release 2014j, a typo inadvertently
907    suppressed the change.  (Thanks to Alois Treindl.)
908
909    Detroit observed DST in 1967 and 1968 following the US DST rules,
910    except that its 1967 DST began on June 14 at 00:01.  (Thanks to
911    Alois Treindl for pointing out that the old data entries were
912    probably wrong.)
913
914    Fix several errors in pre-1970 transitions in Perry County, IN.
915    (Thanks to Alois Treindl for pointing out the 1967/9 errors.)
916
917    Edmonton did not observe DST in 1967 or 1969.  In 1946 Vancouver
918    ended DST on 09-29 not 10-13, and Vienna ended DST on 10-07 not
919    10-06.  In 1945 Königsberg (now Kaliningrad) switched from +01/+02
920    to +02/+03 on 04-10 not 01-01, and its +02/+03 is abbreviated
921    EET/EEST, not CET/CEST.  (Thanks to Alois Treindl.)  In 1946
922    Königsberg switched to +03 on 04-07 not 01-01.
923
924    In 1946 Louisville switched from CST to CDT on 04-28 at 00:01, not
925    01-01 at 00:00.  (Thanks to Alois Treindl and Michael Deckers.)
926    Also, it switched from CST to CDT on 1950-04-30, not 1947-04-27.
927
928    The 1892-05-01 transition in Brussels was at 00:17:30, not at noon.
929    (Thanks to Michael Deckers.)
930
931  Changes to past time zone abbreviations and DST flags
932
933    Hong Kong Winter Time, observed from 1941-10-01 to 1941-12-25,
934    is now flagged as DST and is abbreviated HKWT not HKT.
935
936  Changes to code
937
938    leapseconds.awk now relies only on its input data, rather than
939    also relying on its comments.  (Inspired by code from Dennis
940    Ferguson and Chris Woodbury.)
941
942    The code now defends against CRLFs in leap-seconds.list.
943    (Thanks to Brian Inglis and Chris Woodbury.)
944
945  Changes to documentation and commentary
946
947    theory.html discusses leap seconds.  (Thanks to Steve Summit.)
948
949    Nashville's newspapers dueled about the time of day in the 1950s.
950    (Thanks to John Seigenthaler.)
951
952    Liechtenstein observed Swiss DST in 1941/2.
953    (Thanks to Alois Treindl.)
954
955
956Release 2019b - 2019-07-01 00:09:53 -0700
957
958  Briefly:
959    Brazil no longer observes DST.
960    'zic -b slim' outputs smaller TZif files; please try it out.
961    Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
962
963  Changes to future timestamps
964
965    Brazil has canceled DST and will stay on standard time indefinitely.
966    (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
967    Oliveira.)
968
969    Predictions for Morocco now go through 2087 instead of 2037, to
970    work around a problem on newlib when using TZif files output by
971    zic 2019a or earlier.  (Problem reported by David Gauchard.)
972
973  Changes to past and future timestamps
974
975    Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
976    at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
977    future transitions to be March's last Friday at 00:00.
978
979  Changes to past timestamps
980
981    Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
982    03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
983    not 09-15 at 00:00.  In 1946 its spring-forward transition was on
984    04-21 at 00:00, not the previous day at 03:30.  From 1946 through
985    1952 its fall-back transitions occurred at 04:30, not at 03:30.
986    In 1947 its fall-back transition was on 11-30, not 12-30.
987    (Thanks to P Chan.)
988
989  Changes to past time zone abbreviations
990
991    Italy's 1866 transition to Rome Mean Time was on December 12, not
992    September 22.  This affects only the time zone abbreviation for
993    Europe/Rome between those dates.  (Thanks to Stephen Trainor and
994    Luigi Rosa.)
995
996  Changes affecting metadata only
997
998    Add info about the Crimea situation in zone1970.tab and zone.tab.
999    (Problem reported by Serhii Demediuk.)
1000
1001  Changes to code
1002
1003    zic's new -b option supports a way to control data bloat and to
1004    test for year-2038 bugs in software that reads TZif files.
1005    'zic -b fat' and 'zic -b slim' generate larger and smaller output;
1006    for example, changing from fat to slim shrinks the Europe/London
1007    file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
1008    files represent the same set of timestamps and use the same TZif
1009    format as documented in tzfile(5) and in Internet RFC 8536.
1010    Fat format attempts to work around bugs or incompatibilities in
1011    older software, notably software that mishandles 64-bit TZif data
1012    or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
1013    Slim format is more efficient and does not work around 64-bit bugs
1014    or obsolete TZ strings.  Currently zic defaults to fat format
1015    unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
1016    out-of-the-box default is intended to change in future releases
1017    as the buggy software often mishandles timestamps anyway.
1018
1019    zic no longer treats a set of rules ending in 2037 specially.
1020    Previously, zic assumed that such a ruleset meant that future
1021    timestamps could not be predicted, and therefore omitted a
1022    POSIX-like TZ string in the TZif output.  The old behavior is no
1023    longer needed for current tzdata, and caused problems with newlib
1024    when used with older tzdata (reported by David Gauchard).
1025
1026    zic no longer generates some artifact transitions.  For example,
1027    Europe/London no longer has a no-op transition in January 1996.
1028
1029  Changes to build procedure
1030
1031    tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
1032    by a percent or so.
1033
1034  Changes to documentation and commentary
1035
1036    The Makefile now documents the POSIXRULES macro as being obsolete,
1037    and similarly, zic's -p POSIXRULES option is now documented as
1038    being obsolete.  Although the POSIXRULES feature still exists and
1039    works as before, in practice it is rarely used for its intended
1040    purpose, and it does not work either in the default reference
1041    implementation (for timestamps after 2037) or in common
1042    implementations such as GNU/Linux (for contemporary timestamps).
1043    Since POSIXRULES was designed primarily as a temporary transition
1044    facility for System V platforms that died off decades ago, it is
1045    being decommissioned rather than institutionalized.
1046
1047    New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
1048
1049
1050Release 2019a - 2019-03-25 22:01:33 -0700
1051
1052  Briefly:
1053    Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
1054    Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
1055
1056  Changes to past and future timestamps
1057
1058    Palestine will not start DST until 2019-03-30, instead of 2019-03-23 as
1059    previously predicted.  Adjust our prediction by guessing that spring
1060    transitions will be between 24 and 30 March, which matches recent practice
1061    since 2016.  (Thanks to Even Scharning and Tim Parenti.)
1062
1063    Metlakatla ended its observance of Pacific standard time,
1064    rejoining Alaska Time, on 2019-01-20 at 02:00.  (Thanks to Ryan
1065    Stanley and Tim Parenti.)
1066
1067  Changes to past timestamps
1068
1069    Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
1070    (Thanks to Alois Treindl and Isaac Starkman.)
1071
1072  Changes to time zone abbreviations
1073
1074    Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
1075    of being a separate zone that generates the abbreviation "UCT",
1076    which nowadays is typically a typo.  (Problem reported by Isiah
1077    Meadows.)
1078
1079  Changes to code
1080
1081    zic now has an -r option to limit the time range of output data.
1082    For example, 'zic -r @1000000000' limits the output data to
1083    timestamps starting 1000000000 seconds after the Epoch.
1084    This helps shrink output size and can be useful for applications
1085    not needing the full timestamp history, such as TZDIST truncation;
1086    see Internet RFC 8536 section 5.1.  (Inspired by a feature request
1087    from Christopher Wong, helped along by bug reports from Wong and
1088    from Tim Parenti.)
1089
1090  Changes to documentation
1091
1092    Mention Internet RFC 8536 (February 2019), which documents TZif.
1093
1094    tz-link.html now cites tzdata-meta
1095    <https://tzdata-meta.timtimeonline.com/>.
1096
1097
1098Release 2018i - 2018-12-30 11:05:43 -0800
1099
1100  Briefly:
1101    São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.
1102
1103  Changes to future timestamps
1104
1105    Due to a change in government, São Tomé and Príncipe switches back
1106    from +01 to +00 on 2019-01-01 at 02:00.  (Thanks to Vadim
1107    Nasardinov and Michael Deckers.)
1108
1109
1110Release 2018h - 2018-12-23 17:59:32 -0800
1111
1112  Briefly:
1113    Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
1114    New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
1115    Metlakatla, Alaska observes PST this winter only.
1116    Guess Morocco will continue to adjust clocks around Ramadan.
1117    Add predictions for Iran from 2038 through 2090.
1118
1119  Changes to future timestamps
1120
1121    Guess that Morocco will continue to fall back just before and
1122    spring forward just after Ramadan, the practice since 2012.
1123    (Thanks to Maamar Abdelkader.)  This means Morocco will observe
1124    negative DST during Ramadan in main and vanguard formats, and in
1125    rearguard format it stays in the +00 timezone and observes
1126    ordinary DST in all months other than Ramadan.  As before, extend
1127    this guesswork to the year 2037.  As a consequence, Morocco is
1128    scheduled to observe three DST transitions in some Gregorian years
1129    (e.g., 2033) due to the mismatch between the Gregorian and Islamic
1130    calendars.
1131
1132    The table of exact transitions for Iranian DST has been extended.
1133    It formerly cut off before the year 2038 in a nod to 32-bit time_t.
1134    It now cuts off before 2091 as there is doubt about how the Persian
1135    calendar will treat 2091.  This change predicts DST transitions in
1136    2038-9, 2042-3, and 2046-7 to occur one day later than previously
1137    predicted.  As before, post-cutoff transitions are approximated.
1138
1139  Changes to past and future timestamps
1140
1141    Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
1142    +05 on 2018-12-21.  This is a zone split as Qostanay (aka
1143    Kostanay) did not switch, so create a zone Asia/Qostanay.
1144
1145    Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
1146    It did not change clocks that day and remains on -08 this winter.
1147    (Thanks to Ryan Stanley.)  It will revert to the usual Alaska
1148    rules next spring, so this change affects only timestamps
1149    from 2018-11-04 through 2019-03-10.
1150
1151  Change to past timestamps
1152
1153    Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
1154    not 00:00.  I transcribed the time incorrectly from Shanks.
1155    (Thanks to Phake Nick.)
1156
1157    Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
1158    (Thanks to Phake Nick.)
1159
1160    Guam observed DST irregularly from 1959 through 1977.
1161    (Thanks to Phake Nick.)
1162
1163    Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
1164    10-01 changed standard time to +08:30 (not +08).  Its transition
1165    back to +08 after WWII was on 1945-09-15, not the previous day.
1166    Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
1167    (Thanks to Phake Nick, Steve Allen, and Joseph Myers.)  Also,
1168    its 1952 fallback was on 11-02 (not 10-25).
1169
1170    This release contains many changes to timestamps before 1946 due
1171    to Japanese possession or occupation of Pacific/Chuuk,
1172    Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
1173    Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
1174    (Thanks to Phake Nick.)
1175
1176    Assume that the Spanish East Indies was like the Philippines and
1177    observed American time until the end of 1844.  This affects
1178    Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.
1179
1180  Changes to past tm_isdst flags
1181
1182    For the recent Morocco change, the tm_isdst flag should be 1 from
1183    2018-10-27 00:00 to 2018-10-28 03:00.  (Thanks to Michael Deckers.)
1184    Give a URL to the official decree.  (Thanks to Matt Johnson.)
1185
1186
1187Release 2018g - 2018-10-26 22:22:45 -0700
1188
1189  Briefly:
1190    Morocco switches to permanent +01 on 2018-10-28.
1191
1192  Changes to future timestamps
1193
1194    Morocco switches from +00/+01 to permanent +01 effective 2018-10-28,
1195    so its clocks will not fall back as previously scheduled.
1196    (Thanks to Mohamed Essedik Najd and Brian Inglis.)
1197
1198  Changes to code
1199
1200    When generating TZif files with leap seconds, zic no longer uses a
1201    format that trips up older 32-bit clients, fixing a bug introduced
1202    in 2018f.  (Reported by Daniel Fischer.)  Also, the zic workaround
1203    for QTBUG-53071 now also works for TZif files with leap seconds.
1204
1205    The translator to rearguard format now rewrites the line
1206    "Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S" to
1207    "Rule Japan 1948 1951 - Sep Sun>=9  1:00 0 S".
1208    This caters to zic before 2007 and to Oracle TZUpdater 2.2.0
1209    and earlier.  (Reported by Christos Zoulas.)
1210
1211  Changes to past time zone abbreviations
1212
1213    Change HDT to HWT/HPT for WWII-era abbreviations in Hawaii.
1214    This reverts to 2011h, as the abbreviation change in 2011i was
1215    likely inadvertent.
1216
1217  Changes to documentation
1218
1219    tzfile.5 has new sections on interoperability issues.
1220
1221
1222Release 2018f - 2018-10-18 00:14:18 -0700
1223
1224  Briefly:
1225  Volgograd moves from +03 to +04 on 2018-10-28.
1226  Fiji ends DST 2019-01-13, not 2019-01-20.
1227  Most of Chile changes DST dates, effective 2019-04-06.
1228
1229  Changes to future timestamps
1230
1231    Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
1232    (Thanks to Alexander Fetisov and Stepan Golosunov.)
1233
1234    Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
1235    predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
1236    accordingly.
1237
1238    Most of Chile will end DST on the first Saturday in April at 24:00 mainland
1239    time, and resume DST on the first Saturday in September at 24:00 mainland
1240    time.  The changes are effective from 2019-04-06, and do not affect the
1241    Magallanes region modeled by America/Punta_Arenas.  (Thanks to Juan Correa
1242    and Tim Parenti.)  Adjust future predictions accordingly.
1243
1244  Changes to past timestamps
1245
1246    The 2018-05-05 North Korea 30-minute time zone change took place
1247    at 23:30 the previous day, not at 00:00 that day.
1248
1249    China's 1988 spring-forward transition was on April 17, not
1250    April 10.  Its DST transitions in 1986/91 were at 02:00, not 00:00.
1251    (Thanks to P Chan.)
1252
1253    Fix several issues for Macau before 1992.  Macau's pre-1904 LMT
1254    was off by 10 s.  Macau switched to +08 in 1904 not 1912, and
1255    temporarily switched to +09/+10 during World War II.  Macau
1256    observed DST in 1942/79, not 1961/80, and there were several
1257    errors for transition times and dates.  (Thanks to P Chan.)
1258
1259    The 1948-1951 fallback transitions in Japan were at 25:00 on
1260    September's second Saturday, not at 24:00.  (Thanks to Phake Nick.)
1261    zic turns this into 01:00 on the day after September's second
1262    Saturday, which is the best that POSIX or C platforms can do.
1263
1264    Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
1265    paper by Li Yu, replacing more-questionable data from Shanks.
1266
1267  Changes to time zone abbreviations
1268
1269    Use "PST" and "PDT" for Philippine time.  (Thanks to Paul Goyette.)
1270
1271  Changes to code
1272
1273    zic now always generates TZif files where time type 0 is used for
1274    timestamps before the first transition.  This simplifies the
1275    reading of TZif files and should not affect behavior of existing
1276    TZif readers because the same set of time types is used; only
1277    their internal indexes may have changed.  This affects only the
1278    legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
1279    EET, which previously used nonzero types for these timestamps.
1280
1281    Because of the type 0 change, zic no longer outputs a dummy
1282    transition at time -2**59 (before the Big Bang), as clients should
1283    no longer need this to handle historical timestamps correctly.
1284    This reverts a change introduced in 2013d and shrinks most TZif
1285    files by a few bytes.
1286
1287    zic now supports negative time-of-day in Rule and Leap lines, e.g.,
1288    "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
1289    occurs at 18:00 on the Saturday before the last Sunday in April.
1290    This behavior was documented in 2018a but the code did not
1291    entirely match the documentation.
1292
1293    localtime.c no longer requires at least one time type in TZif
1294    files that lack transitions or have a POSIX-style TZ string.  This
1295    future-proofs the code against possible future extensions to the
1296    format that would allow TZif files with POSIX-style TZ strings and
1297    without transitions or time types.
1298
1299    A read-access subscript error in localtime.c has been fixed.
1300    It could occur only in TZif files with timecnt == 0, something that
1301    does not happen in practice now but could happen in future versions.
1302
1303    localtime.c no longer ignores TZif POSIX-style TZ strings that
1304    specify only standard time.  Instead, these TZ strings now
1305    override the default time type for timestamps after the last
1306    transition (or for all timestamps if there are no transitions),
1307    just as DST strings specifying DST have always done.
1308
1309    leapseconds.awk now outputs "#updated" and "#expires" comments,
1310    and supports leap seconds at the ends of months other than June
1311    and December.  (Inspired by suggestions from Chris Woodbury.)
1312
1313  Changes to documentation
1314
1315    New restrictions: A Rule name must start with a character that
1316    is neither an ASCII digit nor "-" nor "+", and an unquoted name
1317    should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
1318    The latter restriction makes room for future extensions (a
1319    possibility noted by Tom Lane).
1320
1321    tzfile.5 now documents what time types apply before the first and
1322    after the last transition, if any.
1323
1324    Documentation now uses the spelling "timezone" for a TZ setting
1325    that determines timestamp history, and "time zone" for a
1326    geographic region currently sharing the same standard time.
1327
1328    The name "TZif" is now used for the tz binary data format.
1329
1330    tz-link.htm now mentions the A0 TimeZone Migration utilities.
1331    (Thanks to Aldrin Martoq for the link.)
1332
1333  Changes to build procedure
1334
1335    New 'make' target 'rearguard_tarballs' to build the rearguard
1336    tarball only.  This is a convenience on platforms that lack lzip
1337    if you want to build the rearguard tarball.  (Problem reported by
1338    Deborah Goldsmith.)
1339
1340    tzdata.zi is now more stable from release to release.  (Problem
1341    noted by Tom Lane.)  It is also a bit shorter.
1342
1343    tzdata.zi now can contain comment lines documenting configuration
1344    information, such as which data format was selected, which input
1345    files were used, and how leap seconds are treated.  (Problems
1346    noted by Lester Caine and Brian Inglis.)  If the Makefile defaults
1347    are used these comment lines are absent, for backward
1348    compatibility.  A redistributor intending to alter its copy of the
1349    files should also append "-LABEL" to the 'version' file's first
1350    line, where "LABEL" identifies the redistributor's change.
1351
1352
1353Release 2018e - 2018-05-01 23:42:51 -0700
1354
1355  Briefly:
1356
1357    North Korea switches back to +09 on 2018-05-05.
1358    The main format uses negative DST again, for Ireland etc.
1359    'make tarballs' now also builds a rearguard tarball.
1360    New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
1361
1362  Changes to past and future timestamps
1363
1364    North Korea switches back from +0830 to +09 on 2018-05-05.
1365    (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
1366    and Tim Parenti.)
1367
1368    Bring back the negative-DST changes of 2018a, except be more
1369    compatible with data parsers that do not support negative DST.
1370    Also, this now affects historical timestamps in Namibia and the
1371    former Czechoslovakia, not just Ireland.  The main format now uses
1372    negative DST to model timestamps in Europe/Dublin (from 1971 on),
1373    Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
1374    does not affect UT offsets, only time zone abbreviations and the
1375    tm_isdst flag.  Also, this does not affect rearguard or vanguard
1376    formats; effectively the main format now uses vanguard instead of
1377    rearguard format.  Data parsers that do not support negative DST
1378    can still use data from the rearguard tarball described below.
1379
1380  Changes to build procedure
1381
1382    The command 'make tarballs' now also builds the tarball
1383    tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
1384    except that it uses rearguard format intended for trailing-edge
1385    data parsers.
1386
1387  Changes to data format and to code
1388
1389    The SAVE column of Rule and Zone lines can now have an 's' or 'd'
1390    suffix, which specifies whether the adjusted time is standard time
1391    or daylight saving time.  If no suffix is given, daylight saving
1392    time is used if and only if the SAVE column is nonzero; this is
1393    the longstanding behavior.  Although this new feature is not used
1394    in tzdata, it could be used to specify the legal time in Namibia
1395    1994-2017, as opposed to the popular time (see below).
1396
1397  Changes to past timestamps
1398
1399    From 1994 through 2017 Namibia observed DST in winter, not summer.
1400    That is, it used negative DST, as Ireland still does.  This change
1401    does not affect UTC offsets; it affects only the tm_isdst flag and
1402    the abbreviation used during summer, which is now CAT, not WAST.
1403    Although (as noted by Michael Deckers) summer and winter time were
1404    both simply called "standard time" in Namibian law, in common
1405    practice winter time was considered to be DST (as noted by Stephen
1406    Colebourne).  The full effect of this change is only in vanguard
1407    and main format; in rearguard format, the tm_isdst flag is still
1408    zero in winter and nonzero in summer.
1409
1410    In 1946/7 Czechoslovakia also observed negative DST in winter.
1411    The full effect of this change is only in vanguard and main
1412    formats; in rearguard format, it is modeled as plain GMT without
1413    daylight saving.  Also, the dates of some 1944/5 DST transitions
1414    in Czechoslovakia have been changed.
1415
1416
1417Release 2018d - 2018-03-22 07:05:46 -0700
1418
1419  Briefly:
1420
1421  Palestine starts DST a week earlier in 2018.
1422  Add support for vanguard and rearguard data consumers.
1423  Add subsecond precision to source data format, though not to data.
1424
1425  Changes to future timestamps
1426
1427    In 2018, Palestine starts DST on March 24, not March 31.
1428    Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
1429
1430  Changes to past and future timestamps
1431
1432    Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
1433    at 04:00.  (Thanks to Steffen Thorsen.)
1434
1435  Changes to past timestamps
1436
1437    Historical transitions for Uruguay, represented by
1438    America/Montevideo, have been updated per official legal documents,
1439    replacing previous data mainly originating from the inventions of
1440    Shanks & Pottenger.  This has resulted in adjustments ranging from
1441    30 to 90 minutes in either direction over at least two dozen
1442    distinct periods ranging from one day to several years in length.
1443    A mere handful of pre-1991 transitions are unaffected; data since
1444    then has come from more reliable contemporaneous reporting.  These
1445    changes affect various timestamps in 1920-1923, 1936, 1939,
1446    1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
1447    Additionally, Uruguay's pre-standard-time UT offset has been
1448    adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
1449    match the location of the Observatory of the National Meteorological
1450    Institute in Montevideo.
1451    (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
1452
1453    East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
1454    (Thanks to Kerry Shetline.)
1455
1456    Fix the 1912-01-01 transition for Portugal and its colonies.
1457    This transition was at 00:00 according to the new UT offset, not
1458    according to the old one.  Also assume that Cape Verde switched on
1459    the same date as the rest, not in 1907.  This affects
1460    Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
1461    Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
1462    (Thanks to Michael Deckers.)
1463
1464    Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
1465    Turks & Caicos.
1466
1467  Changes to past time zone abbreviations
1468
1469    MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
1470    is no clock change associated with the transition.
1471
1472  Changes to build procedure
1473
1474    The new DATAFORM macro in the Makefile lets the installer choose
1475    among three source data formats.  The idea is to lessen downstream
1476    disruption when data formats are improved.
1477
1478    * DATAFORM=vanguard installs from the latest, bleeding-edge
1479      format.  DATAFORM=main (the default) installs from the format
1480      used in the 'africa' etc. files.  DATAFORM=rearguard installs
1481      from a trailing-edge format.  Eventually, elements of today's
1482      vanguard format should move to the main format, and similarly
1483      the main format's features should eventually move to the
1484      rearguard format.
1485
1486    * In the current version, the main and rearguard formats are
1487      identical and match that of 2018c, so this change does not
1488      affect default behavior.  The vanguard format currently contains
1489      one feature not in the main format: negative SAVE values.  This
1490      improves support for Ireland, which uses Irish Standard Time
1491      (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
1492      supported negative SAVE values for decades, and this feature
1493      should move to the main format soon.  However, it will not move
1494      to the rearguard format for quite some time because some
1495      downstream parsers do not support it.
1496
1497    * The build procedure constructs three files vanguard.zi, main.zi,
1498      and rearguard.zi, one for each format.  Although the files
1499      represent essentially the same data, they may have minor
1500      discrepancies that users are not likely to notice.  The files
1501      are intended for downstream data consumers and are not
1502      installed.  Zoneinfo parsers that do not support negative SAVE values
1503      should start using rearguard.zi, so that they will be unaffected
1504      when the negative-DST feature moves from vanguard to main.
1505      Bleeding-edge Zoneinfo parsers that support the new features
1506      already can use vanguard.zi; in this respect, current tzcode is
1507      bleeding-edge.
1508
1509    The Makefile should now be safe for parallelized builds, and 'make
1510    -j to2050new.tzs' is now much faster on a multiprocessor host
1511    with GNU Make.
1512
1513    When built with -DSUPPRESS_TZDIR, the tzcode library no longer
1514    prepends TZDIR/ to file names that do not begin with '/'.  This is
1515    not recommended for general use, due to its security implications.
1516    (From a suggestion by Manuela Friedrich.)
1517
1518  Changes to code
1519
1520    zic now accepts subsecond precision in expressions like
1521    00:19:32.13, which is approximately the legal time of the
1522    Netherlands from 1835 to 1937.  However, because it is
1523    questionable whether the few recorded uses of non-integer offsets
1524    had subsecond precision in practice, there are no plans for tzdata
1525    to use this feature.  (Thanks to Steve Allen for pointing out
1526    the limitations of historical data in this area.)
1527
1528    The code is a bit more portable to MS-Windows.  Installers can
1529    compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
1530    reserve identifiers like 'localtime'.  (Thanks to Manuela
1531    Friedrich.)
1532
1533  Changes to documentation and commentary
1534
1535    theory.html now outlines tzdb's extensions to POSIX's model for
1536    civil time, and has a section "POSIX features no longer needed"
1537    that lists POSIX API components that are now vestigial.
1538    (From suggestions by Steve Summit.)  It also better distinguishes
1539    time zones from tz regions.  (From a suggestion by Guy Harris.)
1540
1541    Commentary is now more consistent about using the phrase "daylight
1542    saving time", to match the C name tm_isdst.  Daylight saving time
1543    need not occur in summer, and need not have a positive offset from
1544    standard time.
1545
1546    Commentary about historical transitions in Uruguay has been expanded
1547    with links to many relevant legal documents.
1548    (Thanks to Tim Parenti.)
1549
1550    Commentary now uses some non-ASCII characters with Unicode value
1551    less than U+0100, as they can be useful and should work even with
1552    older editors such as XEmacs.
1553
1554
1555Release 2018c - 2018-01-22 23:00:44 -0800
1556
1557  Briefly:
1558  Revert Irish changes that relied on negative SAVE values.
1559
1560  Changes to tm_isdst
1561
1562    Revert the 2018a change to Europe/Dublin.  As before, this change
1563    does not affect UT offsets or abbreviations; it affects only
1564    whether timestamps are considered to be standard time or
1565    daylight-saving time, as expressed in the tm_isdst flag of C's
1566    struct tm type.  This reversion is intended to be a temporary
1567    workaround for problems discovered with downstream uses of
1568    releases 2018a and 2018b, which implemented Irish time by using
1569    negative SAVE values in the Eire rules of the 'europe' file.
1570    Although negative SAVE values have been part of tzcode for many
1571    years and are supported by many platforms, they were not
1572    documented before 2018a and ICU and OpenJDK do not currently
1573    support them.  A mechanism to export data to platforms lacking
1574    support for negative DST is planned to be developed before the
1575    change is reapplied.  (Problems reported by Deborah Goldsmith and
1576    Stephen Colebourne.)
1577
1578  Changes to past timestamps
1579
1580    Japanese DST transitions (1948-1951) were Sundays at 00:00, not
1581    Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
1582
1583  Changes to build procedure
1584
1585    The build procedure now works around mawk 1.3.3's lack of support
1586    for character class expressions.  (Problem reported by Ohyama.)
1587
1588
1589Release 2018b - 2018-01-17 23:24:48 -0800
1590
1591  Briefly:
1592  Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
1593
1594  Changes to build procedure
1595
1596    The distribution now contains the file 'pacificnew' again.
1597    This file was inadvertently omitted in the 2018a distribution.
1598    (Problem reported by Matias Fonzo.)
1599
1600
1601Release 2018a - 2018-01-12 22:29:21 -0800
1602
1603  Briefly:
1604  São Tomé and Príncipe switched from +00 to +01.
1605  Brazil's DST will now start on November's first Sunday.
1606  Ireland's standard time is now in the summer, not the winter.
1607  Use Debian-style installation locations, instead of 4.3BSD-style.
1608  New zic option -t.
1609
1610  Changes to past and future timestamps
1611
1612    São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
1613    01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
1614
1615  Changes to future timestamps
1616
1617    Starting in 2018 southern Brazil will begin DST on November's
1618    first Sunday instead of October's third Sunday.  (Thanks to
1619    Steffen Thorsen.)
1620
1621  Changes to past timestamps
1622
1623    A discrepancy of 4 s in timestamps before 1931 in South Sudan has
1624    been corrected.  The 'backzone' and 'zone.tab' files did not agree
1625    with the 'africa' and 'zone1970.tab' files.  (Problem reported by
1626    Michael Deckers.)
1627
1628    The abbreviation invented for Bolivia Summer Time (1931-2) is now
1629    BST instead of BOST, to be more consistent with the convention
1630    used for Latvian Summer Time (1918-9) and for British Summer Time.
1631
1632  Changes to tm_isdst
1633
1634    Change Europe/Dublin so that it observes Irish Standard Time (UT
1635    +01) in summer and GMT (as negative daylight-saving) in winter,
1636    instead of observing standard time (GMT) in winter and Irish
1637    Summer Time (UT +01) in summer.  This change does not affect UT
1638    offsets or abbreviations; it affects only whether timestamps are
1639    considered to be standard time or daylight-saving time, as
1640    expressed in the tm_isdst flag of C's struct tm type.
1641    (Discrepancy noted by Derick Rethans.)
1642
1643  Changes to build procedure
1644
1645    The default installation locations have been changed to mostly
1646    match Debian circa 2017, instead of being designed as an add-on to
1647    4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
1648    TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
1649    USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
1650    locations more precisely.  (This responds to suggestions from
1651    Brian Inglis and from Steve Summit.)
1652
1653    The default installation procedure no longer creates the
1654    backward-compatibility link US/Pacific-New, which causes
1655    confusion during user setup (e.g., see Debian bug 815200).
1656    Use 'make BACKWARD="backward pacificnew"' to create the link
1657    anyway, for now.  Eventually we plan to remove the link entirely.
1658
1659    tzdata.zi now contains a version-number comment.
1660    (Suggested by Tom Lane.)
1661
1662    The Makefile now quotes values like BACKWARD more carefully when
1663    passing them to the shell.  (Problem reported by Zefram.)
1664
1665    Builders no longer need to specify -DHAVE_SNPRINTF on platforms
1666    that have snprintf and use pre-C99 compilers.  (Problem reported
1667    by Jon Skeet.)
1668
1669  Changes to code
1670
1671    zic has a new option -t FILE that specifies the location of the
1672    file that determines local time when TZ is unset.  The default for
1673    this location can be configured via the new TZDEFAULT makefile
1674    macro, which defaults to /etc/localtime.
1675
1676    Diagnostics and commentary now distinguish UT from UTC more
1677    carefully; see theory.html for more information about UT vs UTC.
1678
1679    zic has been ported to GCC 8's -Wstringop-truncation option.
1680    (Problem reported by Martin Sebor.)
1681
1682  Changes to documentation and commentary
1683
1684    The zic man page now documents the longstanding behavior that
1685    times and years can be out of the usual range, with negative times
1686    counting backwards from midnight and with year 0 preceding year 1.
1687    (Problem reported by Michael Deckers.)
1688
1689    The theory.html file now mentions the POSIX limit of six chars
1690    per abbreviation, and lists alphabetic abbreviations used.
1691
1692    The files tz-art.htm and tz-link.htm have been renamed to
1693    tz-art.html and tz-link.html, respectively, for consistency with
1694    other file names and to simplify web server configuration.
1695
1696
1697Release 2017c - 2017-10-20 14:49:34 -0700
1698
1699  Briefly:
1700  Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
1701  Fiji ends DST 2018-01-14, not 2018-01-21.
1702  Namibia switches from +01/+02 to +02 on 2018-04-01.
1703  Sudan switches from +03 to +02 on 2017-11-01.
1704  Tonga likely switches from +13/+14 to +13 on 2017-11-05.
1705  Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
1706  A new file tzdata.zi now holds a small text copy of all data.
1707  The zic input format has been regularized slightly.
1708
1709  Changes to future timestamps
1710
1711    Northern Cyprus has decided to resume EU rules starting
1712    2017-10-29, thus reinstituting winter time.
1713
1714    Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
1715    predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
1716    accordingly.
1717
1718    Namibia will switch from +01 with DST to +02 all year on
1719    2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
1720    at 02:00.  (Thanks to Steffen Thorsen.)
1721
1722    Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
1723    Atyya and Yahia Abdalla.)  South Sudan is not switching, so
1724    Africa/Juba is no longer a link to Africa/Khartoum.
1725
1726    Tonga has likely ended its experiment with DST, and will not
1727    adjust its clocks on 2017-11-05.  Although Tonga has not announced
1728    whether it will continue to observe DST, the IATA is assuming that
1729    it will not.  (Thanks to David Wade.)
1730
1731    Turks & Caicos will switch from -04 all year to -05 with US DST on
1732    2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
1733    at 02:00.  (Thanks to Steffen Thorsen.)
1734
1735  Changes to past timestamps
1736
1737    Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
1738    (Thanks to Arthur David Olson.)
1739
1740    Detroit did not observe DST in 1967.
1741
1742    Use railway time for Asia/Kolkata before 1941, by switching to
1743    Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
1744    1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
1745
1746    Europe/Dublin's 1946 and 1947 fallback transitions occurred at
1747    02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
1748
1749    Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
1750    American time in 1892, not 1879.  (Thanks to Michael Deckers.)
1751
1752    Adjust the 1867 transition in Alaska to better reflect the
1753    historical record, by changing it to occur on 1867-10-18 at 15:30
1754    Sitka time rather than at the start of 1867-10-17 local time.
1755    Although strictly speaking this is accurate only for Sitka,
1756    the rest of Alaska's blanks need to be filled in somehow.
1757
1758    Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
1759    (Thanks to Michael Deckers.)
1760
1761    Add 7 s to the UT offset in Asia/Yangon before 1920.
1762
1763  Changes to zone names
1764
1765    Remove Canada/East-Saskatchewan from the 'backward' file, as it
1766    exceeded the 14-character limit and was an unused misnomer anyway.
1767
1768  Changes to build procedure
1769
1770    To support applications that prefer to read time zone data in text
1771    form, two zic input files tzdata.zi and leapseconds are now
1772    installed by default.  The commands 'zic tzdata.zi' and 'zic -L
1773    leapseconds tzdata.zi' can reproduce the tzdata binary files
1774    without and with leap seconds, respectively.  To prevent these two
1775    new files from being installed, use 'make TZDATA_TEXT=', and to
1776    suppress leap seconds from the tzdata text installation, use 'make
1777    TZDATA_TEXT=tzdata.zi'.
1778
1779    'make BACKWARD=' now suppresses backward-compatibility names
1780    like 'US/Pacific' that are defined in the 'backward' and
1781    'pacificnew' files.
1782
1783    'make check' now works on systems that lack a UTF-8 locale,
1784    or that lack the nsgmls program.  Set UTF8_LOCALE to configure
1785    the name of a UTF-8 locale, if you have one.
1786
1787    Y2K runtime checks are no longer enabled by default.  Add
1788    -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
1789    adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
1790    to disable them.  (New name suggested by Brian Inglis.)
1791
1792    The build procedure for zdump now works on AIX 7.1.
1793    (Problem reported by Kees Dekker.)
1794
1795  Changes to code
1796
1797    zic and the reference runtime now reject multiple leap seconds
1798    within 28 days of each other, or leap seconds before the Epoch.
1799    As a result, support for double leap seconds, which was
1800    obsolescent and undocumented, has been removed.  Double leap
1801    seconds were an error in the C89 standard; they have never existed
1802    in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
1803    noticing glitches in the code that uncovered this problem.)
1804
1805    zic now warns about use of the obsolescent and undocumented -y
1806    option, and about use of the obsolescent TYPE field of Rule lines.
1807
1808    zic now allows unambiguous abbreviations like "Sa" and "Su" for
1809    weekdays; formerly it rejected them due to a bug.  Conversely, zic
1810    no longer considers non-prefixes to be abbreviations; for example,
1811    it no longer accepts "lF" as an abbreviation for "lastFriday".
1812    Also, zic warns about the undocumented usage with a "last-"
1813    prefix, e.g., "last-Fri".
1814
1815    Similarly, zic now accepts the unambiguous abbreviation "L" for
1816    "Link" in ordinary context and for "Leap" in leap-second context.
1817    Conversely, zic no longer accepts non-prefixes such as "La" as
1818    abbreviations for words like "Leap".
1819
1820    zic no longer accepts leap second lines in ordinary input, or
1821    ordinary lines in leap second input.  Formerly, zic sometimes
1822    warned about this undocumented usage and handled it incorrectly.
1823
1824    The new macro HAVE_TZNAME governs whether the tzname external
1825    variable is exported, instead of USG_COMPAT.  USG_COMPAT now
1826    governs only the external variables "timezone" and "daylight".
1827    This change is needed because the three variables are not in the
1828    same category: although POSIX requires tzname, it specifies the
1829    other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
1830    if not defined, the code attempts to guess it from other macros.
1831
1832    localtime.c and difftime.c no longer require stdio.h, and .c files
1833    other than zic.c no longer require sys/wait.h.
1834
1835    zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
1836
1837    Calculation of time_t extrema works around a bug in GCC 4.8.4
1838    (Reported by Stan Shebs and Joseph Myers.)
1839
1840    zic.c no longer mistranslates formats of line numbers in non-English
1841    locales.  (Problem reported by Benno Schulenberg.)
1842
1843    Several minor changes have been made to the code to make it a
1844    bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
1845    Dekker for reporting the problems.)
1846
1847  Changes to documentation and commentary
1848
1849    The two new files 'theory.html' and 'calendars' contain the
1850    contents of the removed file 'Theory'.  The goal is to document
1851    tzdb theory more accessibly.
1852
1853    The zic man page now documents abbreviation rules.
1854
1855    tz-link.htm now covers how to apply tzdata changes to clients.
1856    (Thanks to Jorge Fábregas for the AIX link.)  It also mentions MySQL.
1857
1858    The leap-seconds.list URL has been updated to something that is
1859    more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
1860
1861Release 2017b - 2017-03-17 07:30:38 -0700
1862
1863  Briefly: Haiti has resumed DST.
1864
1865  Changes to past and future timestamps
1866
1867    Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
1868
1869  Changes to past timestamps
1870
1871    Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
1872
1873    Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
1874    is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
1875
1876  Changes to code
1877
1878    The reference localtime implementation now falls back on the
1879    current US daylight-saving transition rules rather than the
1880    1987-2006 rules.  This fallback occurs only when (1) the TZ
1881    environment variable has a value like "AST4ADT" that asks
1882    for daylight saving time but does not specify the rules, (2) there
1883    is no file by that name, and (3) the TZDEFRULES file cannot be
1884    loaded.  (Thanks to Tom Lane.)
1885
1886
1887Release 2017a - 2017-02-28 00:05:36 -0800
1888
1889  Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
1890  discontinues DST.
1891
1892  Changes to future timestamps
1893
1894    Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
1895
1896    Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
1897    Its clocks diverge from America/Santiago starting 2017-05-13 at
1898    23:00, hiving off a new zone America/Punta_Arenas.  Although the
1899    Chilean government says this change expires in May 2019, for now
1900    assume it's permanent.  (Thanks to Juan Correa and Deborah
1901    Goldsmith.)  This also affects Antarctica/Palmer.
1902
1903  Changes to past timestamps
1904
1905    Fix many entries for historical timestamps for Europe/Madrid
1906    before 1979, to agree with tables compiled by Pere Planesas of the
1907    National Astronomical Observatory of Spain.  As a side effect,
1908    this changes some timestamps for Africa/Ceuta before 1929, which
1909    are probably guesswork anyway.  (Thanks to Steve Allen and
1910    Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
1911    correcting the 1901 transition.)
1912
1913    Ecuador observed DST from 1992-11-28 to 1993-02-05.
1914    (Thanks to Alois Treindl.)
1915
1916    Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
1917    (Thanks to Stepan Golosunov.)
1918
1919  Changes to past and future time zone abbreviations
1920
1921    Switch to numeric time zone abbreviations for South America, as
1922    part of the ongoing project of removing invented abbreviations.
1923    This avoids the need to invent an abbreviation for the new Chilean
1924    new zone.  Similarly, switch from invented to numeric time zone
1925    abbreviations for Afghanistan, American Samoa, the Azores,
1926    Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
1927    Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
1928    Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
1929    Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
1930    the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
1931    Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
1932    Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
1933    Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
1934    Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
1935    Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
1936    for half-hour daylight saving time in Belize before 1944 and in
1937    the Dominican Republic before 1975; and for Canary Islands before
1938    1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
1939    Indian Summer Time before 1942, for Indonesia before around 1964,
1940    for Kenya before 1960, for Liberia before 1973, for Madeira before
1941    1967, for Namibia before 1943, for the Netherlands in 1937-9, for
1942    Pakistan before 1971, for Western Sahara before 1977, and for
1943    Zaporozhye in 1880-1924.
1944
1945    For Alaska time from 1900 through 1967, instead of "CAT" use the
1946    abbreviation "AST", the abbreviation commonly used at the time
1947    (Atlantic Standard Time had not been standardized yet).  Use "AWT"
1948    and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
1949
1950    Use "CST" and "CDT" instead of invented abbreviations for Macau
1951    before 1999 and Taiwan before 1938, and use "JST" instead of the
1952    invented abbreviation "JCST" for Japan and Korea before 1938.
1953
1954  Change to database entry category
1955
1956    Move the Pacific/Johnston link from 'australasia' to 'backward',
1957    since Johnston is now uninhabited.
1958
1959  Changes to code
1960
1961    zic no longer mishandles some transitions in January 2038 when it
1962    attempts to work around Qt bug 53071.  This fixes a bug affecting
1963    Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
1964    now contains a workaround, useful when loading a file generated by
1965    a buggy zic.  (Problem and localtime.c fix reported by Bradley
1966    White.)
1967
1968    zdump -i now outputs non-hour numeric time zone abbreviations
1969    without a colon, e.g., "+0530" rather than "+05:30".  This agrees
1970    with zic %z and with common practice, and simplifies auditing of
1971    zdump output.
1972
1973    zdump is now buildable again with -DUSE_LTZ=0.
1974    (Problem reported by Joseph Myers.)
1975
1976    zdump.c now always includes private.h, to avoid code duplication
1977    with private.h.  (Problem reported by Kees Dekker.)
1978
1979    localtime.c no longer mishandles early or late timestamps
1980    when TZ is set to a POSIX-style string that specifies DST.
1981    (Problem reported by Kees Dekker.)
1982
1983    date and strftime now cause %z to generate "-0000" instead of
1984    "+0000" when the UT offset is zero and the time zone abbreviation
1985    begins with "-".
1986
1987  Changes to documentation and commentary
1988
1989    The 'Theory' file now better documents choice of historical time
1990    zone abbreviations.  (Problems reported by Michael Deckers.)
1991
1992    tz-link.htm now covers leap smearing, which is popular in clouds.
1993
1994
1995Release 2016j - 2016-11-22 23:17:13 -0800
1996
1997  Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
1998
1999  Changes to future timestamps
2000
2001    Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
2002    This hives off a new zone Europe/Saratov from Europe/Volgograd.
2003    (Thanks to Yuri Konotopov and Stepan Golosunov.)
2004
2005  Changes to past timestamps
2006
2007    The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
2008    Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
2009    1999, not fall 1994.  (Thanks to Stepan Golosunov.)
2010
2011  Changes to past time zone abbreviations
2012
2013    Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
2014    summer time before 1948.  The old use of "EET" was a typo.
2015
2016  Changes to code
2017
2018    zic no longer mishandles file systems that lack hard links, fixing
2019    bugs introduced in 2016g.  (Problems reported by Tom Lane.)
2020    Also, when the destination already contains symbolic links, zic
2021    should now work better on systems where the 'link' system call
2022    does not follow symbolic links.
2023
2024  Changes to documentation and commentary
2025
2026    tz-link.htm now documents the relationship between release version
2027    numbers and development-repository commit tags.  (Suggested by
2028    Paul Koning.)
2029
2030    The 'Theory' file now documents UT.
2031
2032    iso3166.tab now accents "Curaçao", and commentary now mentions
2033    the names "Cabo Verde" and "Czechia".  (Thanks to Jiří Boháč.)
2034
2035
2036Release 2016i - 2016-11-01 23:19:52 -0700
2037
2038  Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
2039  reintroduces DST on 2016-11-06.
2040
2041  Changes to future timestamps
2042
2043    Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
2044    2017-01-15 at 03:00.  Assume future observances in Tonga will be
2045    from the first Sunday in November through the third Sunday in
2046    January, like Fiji.  (Thanks to Pulu ʻAnau.)  Switch to numeric
2047    time zone abbreviations for this zone.
2048
2049  Changes to past and future timestamps
2050
2051    Northern Cyprus is now +03 year round, causing a split in Cyprus
2052    time zones starting 2016-10-30 at 04:00.  This creates a zone
2053    Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
2054
2055    Antarctica/Casey switched from +08 to +11 on 2016-10-22.
2056    (Thanks to Steffen Thorsen.)
2057
2058  Changes to past timestamps
2059
2060    Several corrections were made for pre-1975 timestamps in Italy.
2061    These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
2062    Europe/Vatican.
2063
2064    First, the 1893-11-01 00:00 transition in Italy used the new UT
2065    offset (+01), not the old (+00:49:56).  (Thanks to Michael
2066    Deckers.)
2067
2068    Second, rules for daylight saving in Italy were changed to agree
2069    with Italy's National Institute of Metrological Research (INRiM)
2070    except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
2071    Inglis, and Michael Deckers):
2072
2073      The 1916-06-03 transition was at 24:00, not 00:00.
2074
2075      The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
2076      00:00, not 01:00.
2077
2078      The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
2079      01:00.
2080
2081      The 1944-09-17 transition was at 03:00, not 01:00.  This
2082      particular change is taken from Italian law as INRiM's table,
2083      (which says 02:00) appears to have a typo here.  Also, keep the
2084      1944-04-03 transition for Europe/Rome, as Rome was controlled by
2085      Germany then.
2086
2087      The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
2088      not 00:00.
2089
2090  Changes to code
2091
2092    The code should now be buildable on AmigaOS merely by setting the
2093    appropriate Makefile variables.  (From a patch by Carsten Larsen.)
2094
2095
2096Release 2016h - 2016-10-19 23:17:57 -0700
2097
2098  Changes to future timestamps
2099
2100    Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
2101    2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
2102    future fall transitions will be on the last Saturday of October
2103    at 01:00, which is consistent with predicted spring transitions
2104    on the last Saturday of March.  (Thanks to Tim Parenti.)
2105
2106  Changes to past timestamps
2107
2108    In Turkey, transitions in 1986-1990 were at 01:00 standard time
2109    not at 02:00, and the spring 1994 transition was on March 20, not
2110    March 27.  (Thanks to Kıvanç Yazan.)
2111
2112  Changes to past and future time zone abbreviations
2113
2114    Asia/Colombo now uses numeric time zone abbreviations like "+0530"
2115    instead of alphabetic ones like "IST" and "LKT".  Various
2116    English-language sources use "IST", "LKT" and "SLST", with no
2117    working consensus.  (Usage of "SLST" mentioned by Sadika
2118    Sumanapala.)
2119
2120  Changes to code
2121
2122    zic no longer mishandles relativizing file names when creating
2123    symbolic links like /etc/localtime, when these symbolic links
2124    are outside the usual directory hierarchy.  This fixes a bug
2125    introduced in 2016g.  (Problem reported by Andreas Stieger.)
2126
2127  Changes to build procedure
2128
2129    New rules 'traditional_tarballs' and 'traditional_signatures' for
2130    building just the traditional-format distribution.  (Requested by
2131    Deborah Goldsmith.)
2132
2133    The file 'version' is now put into the tzdata tarball too.
2134    (Requested by Howard Hinnant.)
2135
2136  Changes to documentation and commentary
2137
2138    The 'Theory' file now has a section on interface stability.
2139    (Requested by Paul Koning.)  It also mentions features like
2140    tm_zone and localtime_rz that have long been supported by the
2141    reference code.
2142
2143    tz-link.htm has improved coverage of time zone boundaries suitable
2144    for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
2145    Johnson.)
2146
2147    The US commentary now mentions Allen and the "day of two noons".
2148
2149    The Fiji commentary mentions the government's 2016-10-03 press
2150    release.  (Thanks to Raymond Kumar.)
2151
2152
2153Release 2016g - 2016-09-13 08:56:38 -0700
2154
2155  Changes to future timestamps
2156
2157    Turkey switched from EET/EEST (+02/+03) to permanent +03,
2158    effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
2159    than an invented abbreviation for the new time.
2160
2161    New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
2162    (Thanks to Tim Parenti.)
2163
2164  Changes to past timestamps
2165
2166    For America/Los_Angeles, spring-forward transition times have been
2167    corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
2168    1950-1966.
2169
2170    For zones using Soviet time on 1919-07-01, transitions to UT-based
2171    time were at 00:00 UT, not at 02:00 local time.  The affected
2172    zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
2173    Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
2174
2175  Changes to past and future time zone abbreviations
2176
2177    The Factory zone now uses the time zone abbreviation -00 instead
2178    of a long English-language string, as -00 is now the normal way to
2179    represent an undefined time zone.
2180
2181    Several zones in Antarctica and the former Soviet Union, along
2182    with zones intended for ships at sea that cannot use POSIX TZ
2183    strings, now use numeric time zone abbreviations instead of
2184    invented or obsolete alphanumeric abbreviations.  The affected
2185    zones are Antarctica/Casey, Antarctica/Davis,
2186    Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
2187    Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
2188    Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
2189    Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
2190    Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
2191    Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
2192    Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
2193    Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
2194    Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
2195    Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
2196    Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
2197    Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
2198    Europe/Minsk, Europe/Samara, Europe/Volgograd, and
2199    Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
2200    was replaced by +05, whereas MSK and MSD were kept as they are not
2201    our invention and are widely used.
2202
2203  Changes to zone names
2204
2205    Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
2206    (Thanks to David Massoud.)
2207
2208  Changes to code
2209
2210    zic no longer generates binary files containing POSIX TZ-like
2211    strings that disagree with the local time type after the last
2212    explicit transition in the data.  This fixes a bug with
2213    Africa/Casablanca and Africa/El_Aaiun in some year-2037 timestamps
2214    on the reference platform.  (Thanks to Alexander Belopolsky for
2215    reporting the bug and suggesting a way forward.)
2216
2217    If the installed localtime and/or posixrules files are symbolic
2218    links, zic now keeps them symbolic links when updating them, for
2219    compatibility with platforms like OpenSUSE where other programs
2220    configure these files as symlinks.
2221
2222    zic now avoids hard linking to symbolic links, avoids some
2223    unnecessary mkdir and stat system calls, and uses shorter file
2224    names internally.
2225
2226    zdump has a new -i option to generate transitions in a
2227    more-compact but still human-readable format.  This option is
2228    experimental, and the output format may change in future versions.
2229    (Thanks to Jon Skeet for suggesting that an option was needed,
2230    and thanks to Tim Parenti and Chris Rovick for further comments.)
2231
2232  Changes to build procedure
2233
2234    An experimental distribution format is available, in addition
2235    to the traditional format which will continue to be distributed.
2236    The new format is a tarball tzdb-VERSION.tar.lz with signature
2237    file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
2238    tzdb-VERSION containing the code and data of the traditional
2239    two-tarball format, along with extra data that may be useful.
2240    (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
2241    for comments about the experimental format.)
2242
2243    The release version number is now more accurate in the usual case
2244    where releases are built from a Git repository.  For example, if
2245    23 commits and some working-file changes have been made since
2246    release 2016g, the version number is now something like
2247    '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
2248    Tagged releases use the same version number format as before,
2249    e.g., '2016g'.  To support the more-accurate version number, its
2250    specification has moved from a line in the Makefile to a new
2251    source file 'version'.
2252
2253    The experimental distribution contains a file to2050.tzs that
2254    contains what should be the output of 'zdump -i -c 2050' on
2255    primary zones.  If this file is available, 'make check' now checks
2256    that zdump generates this output.
2257
2258    'make check_web' now works on Fedora-like distributions.
2259
2260  Changes to documentation and commentary
2261
2262    tzfile.5 now documents the new restriction on POSIX TZ-like
2263    strings that is now implemented by zic.
2264
2265    Comments now cite URLs for some 1917-1921 Russian DST decrees.
2266    (Thanks to Alexander Belopolsky.)
2267
2268    tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
2269    (thanks to Meno Hochschild) and ThreeTen-Extra, and its
2270    description of Java 8 has been brought up to date (thanks to
2271    Stephen Colebourne).  Its description of local time on Mars has
2272    been updated to match current practice, and URLs have been updated
2273    and some obsolete ones removed.
2274
2275
2276Release 2016f - 2016-07-05 16:26:51 +0200
2277
2278  Changes affecting future timestamps
2279
2280    The Egyptian government changed its mind on short notice, and
2281    Africa/Cairo will not introduce DST starting 2016-07-07 after all.
2282    (Thanks to Mina Samuel.)
2283
2284    Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
2285    (Thanks to Stepan Golosunov.)
2286
2287  Changes to past and future timestamps
2288
2289    Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
2290    abbreviations instead of invented ones.
2291
2292  Changes affecting past timestamps
2293
2294    Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
2295    (Thanks to Stepan Golosunov.)
2296
2297
2298Release 2016e - 2016-06-14 08:46:16 -0700
2299
2300  Changes affecting future timestamps
2301
2302    Africa/Cairo observes DST in 2016 from July 7 to the end of October.
2303    Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
2304    For future years, guess April's last Thursday to October's last
2305    Thursday except for Ramadan.
2306
2307  Changes affecting past timestamps
2308
2309    Locations while uninhabited now use '-00', not 'zzz', as a
2310    placeholder time zone abbreviation.  This is inspired by Internet
2311    RFC 3339 and is more consistent with numeric time zone
2312    abbreviations already used elsewhere.  The change affects several
2313    arctic and antarctic locations, e.g., America/Cambridge_Bay before
2314    1920 and Antarctica/Troll before 2005.
2315
2316    Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
2317    at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
2318
2319  Changes to code
2320
2321    zic now outputs a dummy transition at time 2**31 - 1 in zones
2322    whose POSIX-style TZ strings contain a '<'.  This mostly works
2323    around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
2324    (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
2325
2326  Changes affecting documentation and commentary
2327
2328    tz-link.htm says why governments should give plenty of notice for
2329    time zone or DST changes, and refers to Matt Johnson's blog post.
2330
2331    tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
2332
2333
2334Release 2016d - 2016-04-17 22:50:29 -0700
2335
2336  Changes affecting future timestamps
2337
2338    America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
2339    (Thanks to Alexander Krivenyshev for the heads-up.)
2340
2341    Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
2342    (Thanks to Alexander Krivenyshev and Matt Johnson.)
2343
2344    New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
2345    Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
2346    at 02:00.  (Thanks to Stepan Golosunov.)
2347
2348  Changes affecting past timestamps
2349
2350    New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
2351    Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
2352    1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
2353    the same change.  (Thanks to Stepan Golosunov.)
2354
2355    Russia and nearby locations had daylight-saving transitions on
2356    1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
2357    1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
2358    Golosunov.)
2359
2360    Many corrections to historical time in Kazakhstan from 1991
2361    through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
2362    invented time zone abbreviations with numeric abbreviations.
2363
2364  Changes to commentary
2365
2366    Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
2367
2368
2369Release 2016c - 2016-03-23 00:51:27 -0700
2370
2371  Changes affecting future timestamps
2372
2373    Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
2374
2375    Chile reverts from permanent to seasonal DST.  (Thanks to Juan
2376    Correa for the heads-up, and to Tim Parenti for corrections.)
2377    Guess that future transitions are August's and May's second
2378    Saturdays at 24:00 mainland time.  Also, call the period from
2379    2014-09-07 through 2016-05-14 daylight saving time instead of
2380    standard time, as that seems more appropriate now.
2381
2382  Changes affecting past timestamps
2383
2384    Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
2385    +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
2386    from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
2387    (Thanks to Stepan Golosunov.)
2388
2389  Changes to commentary
2390
2391    Several updates and URLs for historical and proposed Russian changes.
2392    (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
2393
2394
2395Release 2016b - 2016-03-12 17:30:14 -0800
2396
2397  Compatibility note
2398
2399    Starting with release 2016b, some data entries cause zic implementations
2400    derived from tz releases 2005j through 2015e to issue warnings like
2401    "time zone abbreviation differs from POSIX standard (+03)".
2402    These warnings should not otherwise affect zic's output and can safely be
2403    ignored on today's platforms, as the warnings refer to a restriction in
2404    POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
2405    warnings is to upgrade to zic derived from tz releases 2015f and later.
2406
2407  Changes affecting future timestamps
2408
2409    New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
2410    Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
2411    2016-03-27 at 02:00 local time.  They need distinct zones since their
2412    post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
2413    Altai Republic, Russia, which will switch from +06 to +07 on the same date
2414    and local time.  The Astrakhan change is already official; the others have
2415    passed the first reading in the State Duma and are extremely likely.
2416    Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
2417    (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
2418    and Stepan Golosunov for followup.)
2419
2420    As a trial of a new system that needs less information to be made up,
2421    the new zones use numeric time zone abbreviations like "+04"
2422    instead of invented abbreviations like "ASTT".
2423
2424    Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
2425    Steffen Thorsen.)
2426
2427    Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
2428    (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
2429    Saturday at 01:00, not March's last Friday at 24:00.
2430
2431  Changes affecting past timestamps
2432
2433    Europe/Chisinau observed DST during 1990, and switched from +04 to
2434    +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
2435    (Thanks to Stepan Golosunov.)
2436
2437    1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
2438    KUYT/KUYST.  (Thanks to Stepan Golosunov.)
2439
2440  Changes to code
2441
2442    tzselect's diagnostics and checking, and checktab.awk's checking,
2443    have been improved.  (Thanks to J William Piggott.)
2444
2445    tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
2446
2447    tzselect now tests Julian-date TZ settings more accurately.
2448    (Thanks to J William Piggott.)
2449
2450  Changes to commentary
2451
2452    Comments in zone tables have been improved.  (Thanks to J William Piggott.)
2453
2454    tzselect again limits its menu comments so that menus fit on a
2455    24×80 alphanumeric display.
2456
2457    A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
2458
2459    In the Theory file, the description of possible time zone abbreviations in
2460    tzdata has been cleaned up, as the old description was unclear and
2461    inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
2462
2463
2464Release 2016a - 2016-01-26 23:28:02 -0800
2465
2466  Changes affecting future timestamps
2467
2468    America/Cayman will not observe daylight saving this year after all.
2469    Revert our guess that it would.  (Thanks to Matt Johnson.)
2470
2471    Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
2472    (Thanks to Alexander Krivenyshev.)
2473
2474    Asia/Tehran now has DST predictions for the year 2038 and later,
2475    to be March 21 00:00 to September 21 00:00.  This is likely better
2476    than predicting no DST, albeit off by a day every now and then.
2477
2478  Changes affecting past and future timestamps
2479
2480    America/Metlakatla switched from PST all year to AKST/AKDT on
2481    2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
2482
2483    America/Santa_Isabel has been removed, and replaced with a
2484    backward compatibility link to America/Tijuana.  Its contents were
2485    apparently based on a misreading of Mexican legislation.
2486
2487  Changes affecting past timestamps
2488
2489    Asia/Karachi's two transition times in 2002 were off by a minute.
2490    (Thanks to Matt Johnson.)
2491
2492  Changes affecting build procedure
2493
2494    An installer can now combine leap seconds with use of the backzone file,
2495    e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
2496    The old 'make posix_packrat' rule is now marked as obsolescent.
2497    (Thanks to Ian Abbott for an initial implementation.)
2498
2499  Changes affecting documentation and commentary
2500
2501    A new file LICENSE makes it easier to see that the code and data
2502    are mostly public-domain.  (Thanks to James Knight.)  The three
2503    non-public-domain files now use the current (3-clause) BSD license
2504    instead of older versions of that license.
2505
2506    tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
2507    CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
2508    on editing tz source files (with a mention of Sublime zoneinfo,
2509    thanks to Gilmore Davidson).
2510
2511    The Theory and asia files now mention the 2015 book "The Global
2512    Transformation of Time, 1870-1950", and cite a couple of reviews.
2513
2514    The America/Chicago entry now documents the informal use of US
2515    central time in Fort Pierre, South Dakota.  (Thanks to Rick
2516    McDermid, Matt Johnson, and Steve Jones.)
2517
2518
2519Release 2015g - 2015-10-01 00:39:51 -0700
2520
2521  Changes affecting future timestamps
2522
2523    Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
2524    (Thanks to Fatih.)
2525
2526    Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
2527    (Thanks to Alexander Krivenyshev.)
2528
2529    Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
2530    (Thanks to Ken Rylander.)
2531
2532    Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
2533    effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
2534    New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
2535
2536  Changes affecting past timestamps
2537
2538    Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
2539
2540  Changes affecting code
2541
2542    localtime no longer mishandles America/Anchorage after 2037.
2543    (Thanks to Bradley White for reporting the bug.)
2544
2545    On hosts with signed 32-bit time_t, localtime no longer mishandles
2546    Pacific/Fiji after 2038-01-16 14:00 UTC.
2547
2548    The localtime module allows the variables 'timezone', 'daylight',
2549    and 'altzone' to be in common storage shared with other modules,
2550    and declares them in case the system <time.h> does not.
2551    (Problems reported by Kees Dekker.)
2552
2553    On platforms with tm_zone, strftime.c now assumes it is not NULL.
2554    This simplifies the code and is consistent with zdump.c.
2555    (Problem reported by Christos Zoulas.)
2556
2557  Changes affecting documentation
2558
2559   The tzfile man page now documents that transition times denote the
2560   starts (not the ends) of the corresponding time periods.
2561   (Ambiguity reported by Bill Seymour.)
2562
2563
2564Release 2015f - 2015-08-10 18:06:56 -0700
2565
2566  Changes affecting future timestamps
2567
2568    North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
2569    The abbreviation remains "KST".  (Thanks to Robert Elz.)
2570
2571    Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
2572    and Pablo Camargo.)
2573
2574  Changes affecting past and future timestamps
2575
2576    Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
2577    (Thanks to Roman Tudos.)
2578
2579  Changes affecting data format and code
2580
2581    zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
2582    field of a Rule line should now be '-'; the old values 'even',
2583    'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
2584    Although the implementation has not changed, these features do not
2585    work in the default installation, they are not used in the data,
2586    and they are now considered obsolescent.
2587
2588    zic now checks that two rules don't take effect at the same time.
2589    (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
2590    simultaneity are now documented.
2591
2592    The two characters '%z' in a zone format now stand for the UT
2593    offset, e.g., '-07' for seven hours behind UT and '+0530' for
2594    five hours and thirty minutes ahead.  This better supports time
2595    zone abbreviations conforming to POSIX.1-2001 and later.
2596
2597  Changes affecting installed data files
2598
2599    Comments for America/Halifax and America/Glace_Bay have been improved.
2600    (Thanks to Brian Inglis.)
2601
2602    Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
2603    Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
2604    installed data files for Europe/Simferopol and Europe/Tallinn.
2605    It does not affect timestamps.  (Thanks to Howard Hinnant.)
2606
2607  Changes affecting code
2608
2609    zdump and zic no longer warn about valid time zone abbreviations
2610    like '-05'.
2611
2612    Some Visual Studio 2013 warnings have been suppressed.
2613    (Thanks to Kees Dekker.)
2614
2615    'date' no longer sets the time of day and its -a, -d, -n and -t
2616    options have been removed.  Long obsolescent, the implementation
2617    of these features had porting problems.  Builders no longer need
2618    to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
2619    (Thanks to Kees Dekker for pointing out the problem.)
2620
2621  Changes affecting documentation
2622
2623    The Theory file mentions naming issues earlier, as these seem to be
2624    poorly publicized (thanks to Gilmore Davidson for reporting the problem).
2625
2626    tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
2627
2628    Mention that Herbert Samuel introduced the term "Summer Time".
2629
2630
2631Release 2015e - 2015-06-13 10:56:02 -0700
2632
2633  Changes affecting future timestamps
2634
2635    Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
2636    not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
2637
2638    Assume Cayman Islands will observe DST starting next year, using US rules.
2639    Although it isn't guaranteed, it is the most likely.
2640
2641  Changes affecting data format
2642
2643    The file 'iso3166.tab' now uses UTF-8, so that its entries can better
2644    spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
2645
2646  Changes affecting code
2647
2648    When displaying data, tzselect converts it to the current locale's
2649    encoding if the iconv command works.  (Problem reported by random832.)
2650
2651    tzselect no longer mishandles Dominica, fixing a bug introduced
2652    in Release 2014f.  (Problem reported by Owen Leibman.)
2653
2654    zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
2655    This fixes a bug introduced in Release 2014f.
2656    (Problem reported by Leonardo Chiquitto.)
2657
2658
2659Release 2015d - 2015-04-24 08:09:46 -0700
2660
2661  Changes affecting future timestamps
2662
2663    Egypt will not observe DST in 2015 and will consider canceling it
2664    permanently.  For now, assume no DST indefinitely.
2665    (Thanks to Ahmed Nazmy and Tim Parenti.)
2666
2667  Changes affecting past timestamps
2668
2669    America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
2670    1966-07-01.  Also, Yukon's time zone history is documented better.
2671    (Thanks to Brian Inglis and Dennis Ferguson.)
2672
2673  Change affecting past and future time zone abbreviations
2674
2675    The abbreviations for Hawaii-Aleutian standard and daylight times
2676    have been changed from HAST/HADT to HST/HDT, as per US Government
2677    Printing Office style.  This affects only America/Adak since 1983,
2678    as America/Honolulu was already using the new style.
2679
2680  Changes affecting code
2681
2682   zic has some minor performance improvements.
2683
2684
2685Release 2015c - 2015-04-11 08:55:55 -0700
2686
2687  Changes affecting future timestamps
2688
2689    Egypt's spring-forward transition is at 24:00 on April's last Thursday,
2690    not 00:00 on April's last Friday.  2015's transition will therefore be on
2691    Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
2692    apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
2693
2694  Changes affecting past timestamps
2695
2696    The following changes affect some pre-1991 Chile-related timestamps
2697    in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
2698
2699      The 1910 transition was January 10, not January 1.
2700
2701      The 1918 transition was September 10, not September 1.
2702
2703      The UT -04 time observed from 1932 to 1942 is now considered to
2704      be standard time, not year-round DST.
2705
2706      Santiago observed DST (UT -03) from 1946-07-15 through
2707      1946-08-31, then reverted to standard time, then switched to -05
2708      on 1947-04-01.
2709
2710      Assume transitions before 1968 were at 00:00, since we have no data
2711      saying otherwise.
2712
2713      The spring 1988 transition was 1988-10-09, not 1988-10-02.
2714      The fall 1990 transition was 1990-03-11, not 1990-03-18.
2715
2716      Assume no UT offset change for Pacific/Easter on 1890-01-01,
2717      and omit all transitions on Pacific/Easter from 1942 through 1946
2718      since we have no data suggesting that they existed.
2719
2720    One more zone has been turned into a link, as it differed
2721    from an existing zone only for older timestamps.  As usual,
2722    this change affects UT offsets in pre-1970 timestamps only.
2723    The zone's old contents have been moved to the 'backzone' file.
2724    The affected zone is America/Montreal.
2725
2726  Changes affecting commentary
2727
2728    Mention the TZUpdater tool.
2729
2730    Mention "The Time Now".  (Thanks to Brandon Ramsey.)
2731
2732
2733Release 2015b - 2015-03-19 23:28:11 -0700
2734
2735  Changes affecting future timestamps
2736
2737    Mongolia will start observing DST again this year, from the last
2738    Saturday in March at 02:00 to the last Saturday in September at 00:00.
2739    (Thanks to Ganbold Tsagaankhuu.)
2740
2741    Palestine will start DST on March 28, not March 27.  Also,
2742    correct the fall 2014 transition from September 26 to October 24.
2743    Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
2744
2745  Changes affecting past timestamps
2746
2747    The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
2748    regression.  (Thanks to Stuart Bishop for reporting the problem.)
2749
2750    Some more zones have been turned into links, when they differed
2751    from existing zones only for older timestamps.  As usual,
2752    these changes affect UT offsets in pre-1970 timestamps only.
2753    Their old contents have been moved to the 'backzone' file.
2754    The affected zones are: America/Antigua, America/Cayman,
2755    Pacific/Midway, and Pacific/Saipan.
2756
2757  Changes affecting time zone abbreviations
2758
2759    Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
2760    (Thanks to Hank W.)
2761
2762  Changes affecting code
2763
2764    Fix integer overflow bug in reference 'mktime' implementation.
2765    (Problem reported by Jörg Richter.)
2766
2767    Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
2768    to be used in the same executable as standard-library time_t functions.
2769    (Problems reported by Bradley White.)
2770
2771  Changes affecting commentary
2772
2773    Cite the recent Mexican decree changing Quintana Roo's time zone.
2774    (Thanks to Carlos Raúl Perasso.)
2775
2776    Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
2777
2778    Update info about Mars time.
2779
2780
2781Release 2015a - 2015-01-29 22:35:20 -0800
2782
2783  Changes affecting future timestamps
2784
2785    The Mexican state of Quintana Roo, represented by America/Cancun,
2786    will shift from Central Time with DST to Eastern Time without DST
2787    on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
2788
2789    Chile will not change clocks in April or thereafter; its new standard time
2790    will be its old daylight saving time.  This affects America/Santiago,
2791    Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
2792
2793    New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
2794    (Thanks to Tim Parenti.)
2795
2796  Changes affecting past timestamps
2797
2798    Iceland observed DST in 1919 and 1921, and its 1939 fallback
2799    transition was Oct. 29, not Nov. 29.  Remove incorrect data from
2800    Shanks about time in Iceland between 1837 and 1908.
2801
2802    Some more zones have been turned into links, when they differed
2803    from existing zones only for older timestamps.  As usual,
2804    these changes affect UT offsets in pre-1970 timestamps only.
2805    Their old contents have been moved to the 'backzone' file.
2806    The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
2807    and Asia/Muscat.
2808
2809  Changes affecting code
2810
2811    tzalloc now scrubs time zone abbreviations compatibly with the way
2812    that tzset always has, by replacing invalid bytes with '_' and by
2813    shortening too-long abbreviations.
2814
2815    tzselect ports to POSIX awk implementations, no longer mishandles
2816    POSIX TZ settings when GNU awk is used, and reports POSIX TZ
2817    settings to the user.  (Thanks to Stefan Kuhn.)
2818
2819  Changes affecting build procedure
2820
2821    'make check' now checks for links to links in the data.
2822    One such link (for Africa/Asmera) has been fixed.
2823    (Thanks to Stephen Colebourne for pointing out the problem.)
2824
2825  Changes affecting commentary
2826
2827    The leapseconds file commentary now mentions the expiration date.
2828    (Problem reported by Martin Burnicki.)
2829
2830    Update Mexican Library of Congress URL.
2831
2832
2833Release 2014j - 2014-11-10 17:37:11 -0800
2834
2835  Changes affecting current and future timestamps
2836
2837    Turks & Caicos' switch from US eastern time to UT -04 year-round
2838    did not occur on 2014-11-02 at 02:00.  It's currently scheduled
2839    for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
2840
2841  Changes affecting past timestamps
2842
2843    Many pre-1989 timestamps have been corrected for Asia/Seoul and
2844    Asia/Pyongyang, based on sources for the Korean-language Wikipedia
2845    entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
2846    longer guess that Pyongyang mimicked Seoul time after World War II,
2847    as this is politically implausible.
2848
2849    Some more zones have been turned into links, when they differed
2850    from existing zones only for older timestamps.  As usual,
2851    these changes affect UT offsets in pre-1970 timestamps only.
2852    Their old contents have been moved to the 'backzone' file.
2853    The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
2854    Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
2855    Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
2856    Indian/Mayotte.
2857
2858  Changes affecting commentary
2859
2860    The commentary is less enthusiastic about Shanks as a source,
2861    and is more careful to distinguish UT from UTC.
2862
2863
2864Release 2014i - 2014-10-21 22:04:57 -0700
2865
2866  Changes affecting future timestamps
2867
2868    Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
2869    (Thanks to Ken Rylander for the heads-up.)  Guess that future
2870    years will use a similar pattern.
2871
2872    A new Zone Pacific/Bougainville, for the part of Papua New Guinea
2873    that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
2874    (Thanks to Kiley Walbom for the heads-up.)
2875
2876  Changes affecting time zone abbreviations
2877
2878    Since Belarus is not changing its clocks even though Moscow is,
2879    the time zone abbreviation in Europe/Minsk is changing from FET
2880    to its more-traditional value MSK on 2014-10-26 at 01:00.
2881    (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
2882
2883    The new abbreviation IDT stands for the pre-1976 use of UT +08 in
2884    Indochina, to distinguish it better from ICT (+07).
2885
2886  Changes affecting past timestamps
2887
2888    Many timestamps have been corrected for Asia/Ho_Chi_Minh before 1976
2889    (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
2890    authoritative book).  Asia/Ho_Chi_Minh has been added to
2891    zone1970.tab, to give tzselect users in Vietnam two choices,
2892    since north and south Vietnam disagreed after our 1970 cutoff.
2893
2894    Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
2895    they differed from existing zones only for older timestamps.  As
2896    usual, these changes affect pre-1970 timestamps only.  Their old
2897    contents have been moved to the 'backzone' file.
2898
2899  Changes affecting code
2900
2901    The time-related library functions now set errno on failure, and
2902    some crashes in the new tzalloc-related library functions have
2903    been fixed.  (Thanks to Christos Zoulas for reporting most of
2904    these problems and for suggesting fixes.)
2905
2906    If USG_COMPAT is defined and the requested timestamp is standard time,
2907    the tz library's localtime and mktime functions now set the extern
2908    variable timezone to a value appropriate for that timestamp; and
2909    similarly for ALTZONE, daylight saving time, and the altzone variable.
2910    This change is a companion to the tzname change in 2014h, and is
2911    designed to make timezone and altzone more compatible with tzname.
2912
2913    The tz library's functions now set errno to EOVERFLOW if they fail
2914    because the result cannot be represented.  ctime and ctime_r now
2915    return NULL and set errno when a timestamp is out of range, rather
2916    than having undefined behavior.
2917
2918    Some bugs associated with the new 2014g functions have been fixed.
2919    This includes a bug that largely incapacitated the new functions
2920    time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
2921    It also includes some uses of uninitialized variables after tzalloc.
2922    The new code uses the standard type 'ssize_t', which the Makefile
2923    now gives porting advice about.
2924
2925  Changes affecting commentary
2926
2927    Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
2928
2929
2930Release 2014h - 2014-09-25 18:59:03 -0700
2931
2932  Changes affecting past timestamps
2933
2934    America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
2935
2936    Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
2937    not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
2938
2939    Some more zones have been turned into links, when they differed
2940    from existing zones only for older timestamps.  As usual,
2941    these changes affect UT offsets in pre-1970 timestamps only.
2942    Their old contents have been moved to the 'backzone' file.
2943    The affected zones are: Africa/Blantyre, Africa/Bujumbura,
2944    Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
2945    Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
2946
2947  Changes affecting code
2948
2949    zdump -V and -v now output gmtoff= values on all platforms,
2950    not merely on platforms defining TM_GMTOFF.
2951
2952    The tz library's localtime and mktime functions now set tzname to a value
2953    appropriate for the requested timestamp, and zdump now uses this
2954    on platforms not defining TM_ZONE, fixing a 2014g regression.
2955    (Thanks to Tim Parenti for reporting the problem.)
2956
2957    The tz library no longer sets tzname if localtime or mktime fails.
2958
2959    zdump -c no longer mishandles transitions near year boundaries.
2960    (Thanks to Tim Parenti for reporting the problem.)
2961
2962    An access to uninitialized data has been fixed.
2963    (Thanks to Jörg Richter for reporting the problem.)
2964
2965    When THREAD_SAFE is defined, the code ports to the C11 memory model.
2966    A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
2967    and two threads race to initialize data used by gmtime-like functions.
2968    (Thanks to Andy Heninger for reporting the problems.)
2969
2970  Changes affecting build procedure
2971
2972    'make check' now checks better for properly-sorted data.
2973
2974  Changes affecting documentation and commentary
2975
2976    zdump's gmtoff=N output is now documented, and its isdst=D output
2977    is now documented to possibly output D values other than 0 or 1.
2978
2979    zdump -c's treatment of years is now documented to use the
2980    Gregorian calendar and Universal Time without leap seconds,
2981    and its behavior at cutoff boundaries is now documented better.
2982    (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
2983
2984    Programs are now documented to use the proleptic Gregorian calendar.
2985    (Thanks to Alan Barrett for the suggestion.)
2986
2987    Fractional-second GMT offsets have been documented for civil time
2988    in 19th-century Chennai, Jakarta, and New York.
2989
2990
2991Release 2014g - 2014-08-28 12:31:23 -0700
2992
2993  Changes affecting future timestamps
2994
2995    Turks & Caicos is switching from US eastern time to UT -04
2996    year-round, modeled as a switch on 2014-11-02 at 02:00.
2997    [As noted in 2014j, this switch was later delayed.]
2998
2999  Changes affecting past timestamps
3000
3001    Time in Russia or the USSR before 1926 or so has been corrected by
3002    a few seconds in the following zones: Asia/Irkutsk,
3003    Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
3004    Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
3005    Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
3006    Vladimir Karpinsky.)
3007
3008    The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
3009    This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
3010    Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
3011    GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
3012    (Thanks to Stephen Colebourne for pointing to the decree.)
3013
3014    Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
3015
3016    A new file 'backzone' contains data which may appeal to
3017    connoisseurs of old timestamps, although it is out of scope for
3018    the tz database, is often poorly sourced, and contains some data
3019    that is known to be incorrect.  The new file is not recommended
3020    for ordinary use and its entries are not installed by default.
3021    (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
3022    Isle of Man entries.)
3023
3024    Some more zones have been turned into links, when they differed
3025    from existing zones only for older timestamps.  As usual,
3026    these changes affect UT offsets in pre-1970 timestamps only.
3027    Their old contents have been moved to the 'backzone' file.
3028    The affected zones are: Africa/Bangui, Africa/Brazzaville,
3029    Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
3030    Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
3031
3032  Changes affecting code
3033
3034    Unless NETBSD_INSPIRED is defined to 0, the tz library now
3035    supplies functions for creating and using objects that represent
3036    timezones. The new functions are tzalloc, tzfree, localtime_rz,
3037    mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
3038    time2posix_z.  They are intended for performance: for example,
3039    localtime_rz (unlike localtime_r) is trivially thread-safe without
3040    locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
3041    functions, and to Alan Barrett and Jonathan Lennox for helping to
3042    debug the change.)
3043
3044    zdump now builds with the tz library unless USE_LTZ is defined to 0,
3045    This lets zdump use tz features even if the system library lacks them.
3046    To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
3047    TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
3048
3049    zdump now uses localtime_rz if available, as it's significantly faster,
3050    and it can help zdump better diagnose invalid timezone names.
3051    Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
3052    defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
3053    not available, zdump now uses localtime_r and tzset if available,
3054    as this is a bit cleaner and faster than plain localtime.  Compile
3055    with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
3056    lacks these two functions.
3057
3058    If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
3059    Although not needed for tz's own applications, which are single-threaded,
3060    this supports POSIX better if the tz library is used in multithreaded apps.
3061
3062    Some crashes have been fixed when zdump or the tz library is given
3063    invalid or outlandish input.
3064
3065    The tz library no longer mishandles leap seconds on platforms with
3066    unsigned time_t in timezones that lack ordinary transitions after 1970.
3067
3068    The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
3069    already defined, to make it easier to configure on common platforms.
3070    Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
3071
3072    Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
3073    assumes that reading uninitialized memory yields garbage values
3074    but does not cause other problems such as traps.
3075
3076    If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
3077    more likely to guess right for ambiguous timestamps near
3078    transitions where tm_isdst does not change.
3079
3080    If HAVE_STRFTIME_L is defined to 1, the tz library now defines
3081    strftime_l for compatibility with recent versions of POSIX.
3082    Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
3083    to 1 on recent POSIX versions, and to 0 otherwise.
3084
3085    tzselect -c now uses a hybrid distance measure that works better
3086    in Africa.  (Thanks to Alan Barrett for noting the problem.)
3087
3088    The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
3089    or when time_tz is defined.
3090
3091    When HAVE_UTMPX_H is set the 'date' command now builds on systems
3092    whose <utmpx.h> file does not define WTMPX_FILE, and when setting
3093    the date it updates the wtmpx file if _PATH_WTMPX is defined.
3094    This affects GNU/Linux and similar systems.
3095
3096    For easier maintenance later, some C code has been simplified,
3097    some lint has been removed, and the code has been tweaked so that
3098    plain 'make' is more likely to work.
3099
3100    The C type 'bool' is now used for boolean values, instead of 'int'.
3101
3102    The long-obsolete LOCALE_HOME code has been removed.
3103
3104    The long-obsolete 'gtime' function has been removed.
3105
3106  Changes affecting build procedure
3107
3108    'zdump' no longer links in ialloc.o, as it's not needed.
3109
3110    'make check_time_t_alternatives' no longer assumes GNU diff.
3111
3112  Changes affecting distribution tarballs
3113
3114    The files checktab.awk and zoneinfo2tdf.pl are now distributed in
3115    the tzdata tarball instead of the tzcode tarball, since they help
3116    maintain the data.  The NEWS and Theory files are now also
3117    distributed in the tzdata tarball, as they're relevant for data.
3118    (Thanks to Alan Barrett for pointing this out.)  Also, the
3119    leapseconds.awk file is no longer distributed in the tzcode
3120    tarball, since it belongs in the tzdata tarball (where 2014f
3121    inadvertently also distributed it).
3122
3123  Changes affecting documentation and commentary
3124
3125    A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
3126    suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
3127    for debugging it.)
3128
3129    The man pages have been updated to use function prototypes,
3130    to document thread-safe variants like localtime_r, and to document
3131    the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
3132    mktime_z.
3133
3134    The fields in Link lines have been renamed to be more descriptive
3135    and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
3136    and LINK-TO has become LINK-NAME.
3137
3138    tz-link.htm mentions the IETF's tzdist working group; Windows
3139    Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
3140
3141    Some broken URLs have been fixed in the commentary.  (Thanks to
3142    Lester Caine.)
3143
3144    Commentary about Philippines DST has been updated, and commentary
3145    on pre-1970 time in India has been added.
3146
3147
3148Release 2014f - 2014-08-05 17:42:36 -0700
3149
3150  Changes affecting future timestamps
3151
3152    Russia will subtract an hour from most of its time zones on 2014-10-26
3153    at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
3154    There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
3155    Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
3156    (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
3157    (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
3158    (Europe/Samara) are not changing their clocks.  The changed zones are
3159    Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
3160    Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
3161    Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
3162    Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
3163    subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
3164    but not its UTC offset.  Two zones are added: Asia/Chita (split
3165    from Asia/Yakutsk, and also with two hours subtracted) and
3166    Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
3167    subtracted).  (Thanks to Tim Parenti for much of the above.)
3168
3169  Changes affecting time zone abbreviations
3170
3171    Australian eastern time zone abbreviations are now AEST/AEDT not EST,
3172    and similarly for the other Australian zones.  That is, for eastern
3173    standard and daylight saving time the abbreviations are AEST and AEDT
3174    instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
3175    and AWST/AWDT are now used instead of the former CST, CWST, and WST.
3176    This change does not affect UT offsets, only time zone abbreviations.
3177    (Thanks to Rich Tibbett and many others.)
3178
3179    Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
3180    effective 2014-10-26 at 02:00 local time.
3181
3182    The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
3183    has been changed from URUT to XJT.  (Thanks to Luther Ma.)
3184
3185    Prefer MSK/MSD for Moscow time in Russia, even in other cities.
3186    Similarly, prefer EET/EEST for eastern European time in Russia.
3187
3188    Change time zone abbreviations in (western) Samoa to use "ST" and
3189    "DT" suffixes, as this is more likely to match common practice.
3190    Prefix "W" to (western) Samoa time when its standard-time offset
3191    disagrees with that of American Samoa.
3192
3193    America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
3194
3195    Time zone abbreviations have been updated for Japan's two time
3196    zones used 1896-1937.  JWST now stands for Western Standard
3197    Time, and JCST for Central Standard Time (formerly this was CJT).
3198    These abbreviations are now used for time in Korea, Taiwan,
3199    and Sakhalin while controlled by Japan.
3200
3201  Changes affecting past timestamps
3202
3203    China's five zones have been simplified to two, since the post-1970
3204    differences in the other three seem to have been imaginary.  The
3205    zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
3206    removed; backwards-compatibility links still work, albeit with
3207    different behaviors for timestamps before May 1980.  Asia/Urumqi's
3208    1980 transition to UT +08 has been removed, so that it is now at
3209    +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
3210    Treindl sent helpful translations of two papers by Guo Qingsheng.)
3211
3212    Some zones have been turned into links, when they differed from existing
3213    zones only for older UT offsets where data entries were likely invented.
3214    These changes affect UT offsets in pre-1970 timestamps only.  This is
3215    similar to the change in release 2013e, except this time for western
3216    Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
3217    Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
3218    Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
3219    Atlantic/St_Helena.  This also affects the backwards-compatibility
3220    link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
3221    Tim Parenti, and David Patte for reporting problems in earlier
3222    versions of this change.)
3223
3224    Asia/Shanghai's pre-standard-time UT offset has been changed from
3225    8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
3226    transition to standard time has been changed from 1928 to 1901.
3227
3228    Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
3229    then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
3230    In 1946 it observed DST from 05-15 through 09-30; in 1947
3231    from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
3232    (Thanks to Yu-Cheng Chuang.)
3233
3234    Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
3235
3236    Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
3237    10-03 at 00:00.  (Thanks to Konstantin Hyppönen.)
3238
3239    Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
3240    period from 1911 to 1950.
3241
3242    Pacific/Chatham has been changed to New Zealand standard time plus
3243    45 minutes for the period before 1957, reflecting a 1956 remark in
3244    the New Zealand parliament.
3245
3246    Europe/Budapest has several pre-1946 corrections: in 1918 the transition
3247    out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
3248    1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
3249    not 04-06 at 02:00; and there was no DST in 1920.
3250
3251    Africa/Accra is now assumed to have observed DST from 1920 through 1935.
3252
3253    Time in Russia before 1927 or so has been corrected by a few seconds in
3254    the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
3255    Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
3256    Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
3257    point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
3258
3259  Changes affecting data format
3260
3261    A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
3262    The new file's extended format allows multiple country codes per zone.
3263    The older file is still installed but is deprecated; its format is
3264    not changing and it will still be distributed for a while, but new
3265    applications should use the new file.
3266
3267    The new file format simplifies maintenance of obscure locations.
3268    To test this, it adds coverage for the Crozet Islands and the
3269    Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
3270
3271    The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
3272    It is still ASCII now, but commentary about the switch has been added.
3273    The new file 'zone1970.tab' already uses UTF-8.
3274
3275  Changes affecting code
3276
3277    'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
3278    is defined.  (Thanks to Elliott Hughes for reporting the problem.)
3279
3280    'zic' no longer mishandles input when ignoring case in locales that
3281    are not compatible with English, e.g., unibyte Turkish locales when
3282    compiled with HAVE_GETTEXT.
3283
3284    Error diagnostics of 'zic' and 'yearistype' have been reworded so that
3285    they no longer use ASCII '-' as if it were a dash.
3286
3287    'zic' now rejects output file names that contain '.' or '..' components.
3288    (Thanks to Tim Parenti for reporting the problem.)
3289
3290    'zic -v' now warns about output file names that do not follow
3291    POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
3292    David Olson for starting the ball rolling on this.)
3293
3294    Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
3295
3296  Changes affecting build procedure
3297
3298    'zic' no longer links in localtime.o and asctime.o, as they're not needed.
3299    (Thanks to John Cochran.)
3300
3301  Changes affecting documentation and commentary
3302
3303    The 'Theory' file documents legacy names, the longstanding
3304    exceptions to the POSIX-inspired file name rules.
3305
3306    The 'zic' documentation clarifies the role of time types when
3307    interpreting dates.  (Thanks to Arthur David Olson.)
3308
3309    Documentation and commentary now prefer UTF-8 to US-ASCII,
3310    allowing the use of proper accents in foreign words and names.
3311    Code and data have not changed because of this.  (Thanks to
3312    Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
3313    this.)
3314
3315    Non-HTML documentation and commentary now use plain-text URLs instead of
3316    HTML insertions, and are more consistent about bracketing URLs when they
3317    are not already surrounded by white space.  (Thanks to suggestions by
3318    Steffen Nurpmeso.)
3319
3320    There is new commentary about Xujiahui Observatory, the five time-zone
3321    project in China from 1918 to 1949, timekeeping in Japanese-occupied
3322    Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
3323    warlord Jin Shuren in the data.
3324
3325    Commentary about the coverage of each Russian zone has been standardized.
3326    (Thanks to Tim Parenti.)
3327
3328    There is new commentary about contemporary timekeeping in Ethiopia.
3329
3330    Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
3331
3332    There is new commentary about time in Poland in 1919.
3333
3334    Proper credit has been given to DST inventor George Vernon Hudson.
3335
3336    Commentary about time in Metlakatla, AK and Resolute, NU has been
3337    improved, with a new source for the former.
3338
3339    In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
3340    is uninhabited.
3341
3342    Commentary about permanent Antarctic bases has been updated.
3343
3344    Several typos have been corrected.  (Thanks to Tim Parenti for
3345    contributing some of these fixes.)
3346
3347    tz-link.htm now mentions the JavaScript libraries Moment Timezone,
3348    TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
3349    from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
3350    (Thanks to a heads-up from Dirkjan Ochtman.)
3351
3352    The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
3353    have been removed.  These obsolescent US Naval Observatory entries were no
3354    longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
3355
3356
3357Release 2014e - 2014-06-12 21:53:52 -0700
3358
3359  Changes affecting near-future timestamps
3360
3361    Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
3362    (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
3363    switch to standard time at 24:00 the last Thursday before Ramadan, and
3364    back to DST at 00:00 the first Friday after Ramadan.
3365
3366    Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
3367    to Milamber Space Network.)  Guess that from 2015 on Morocco will
3368    temporarily switch to standard time at 03:00 the last Saturday before
3369    Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
3370
3371  Changes affecting past timestamps
3372
3373    The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
3374    "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
3375    "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
3376    in 1991.  (Thanks to Hank W. for reporting the problems.)
3377
3378  Changes affecting commentary
3379
3380    tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
3381    draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
3382    removes stale pointers to World Time Explorer and WORLDTIME.
3383
3384
3385Release 2014d - 2014-05-27 21:34:40 -0700
3386
3387  Changes affecting code
3388
3389    zic no longer generates files containing timestamps before the Big Bang.
3390    This works around GNOME glib bug 878
3391    <https://gitlab.gnome.org/GNOME/glib/issues/878>
3392    (Thanks to Leonardo Chiquitto for reporting the bug, and to
3393    Arthur David Olson and James Cloos for suggesting improvements to the fix.)
3394
3395  Changes affecting documentation
3396
3397    tz-link.htm now mentions GNOME.
3398
3399
3400Release 2014c - 2014-05-13 07:44:13 -0700
3401
3402  Changes affecting near-future timestamps
3403
3404    Egypt observes DST starting 2014-05-15 at 24:00.
3405    (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
3406    Details have not been announced, except that DST will not be observed
3407    during Ramadan.  Guess that DST will stop during the same Ramadan dates as
3408    Morocco, and that Egypt's future spring and fall transitions will be the
3409    same as 2010 when it last observed DST, namely April's last Friday at
3410    00:00 to September's last Thursday at 23:00 standard time.  Also, guess
3411    that Ramadan transitions will be at 00:00 standard time.
3412
3413  Changes affecting code
3414
3415    zic now generates transitions for minimum time values, eliminating guesswork
3416    when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
3417
3418    Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
3419
3420  Changes affecting commentary and documentation
3421
3422    Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
3423
3424
3425Release 2014b - 2014-03-24 21:28:50 -0700
3426
3427  Changes affecting near-future timestamps
3428
3429    Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
3430    (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
3431
3432    New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
3433    Bengt-Inge Larsson.)  This is currently an approximation; a better version
3434    will require the zic and localtime fixes mentioned below, and the plan is
3435    to wait for a while until at least the zic fixes propagate.
3436
3437  Changes affecting code
3438
3439    'zic' and 'localtime' no longer reject locations needing four transitions
3440    per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
3441    Also, 'zic' avoids some unlikely failures due to integer overflow.
3442
3443  Changes affecting build procedure
3444
3445    'make check' now detects Rule lines defined but never used.
3446    The NZAQ rules, an instance of this problem, have been removed.
3447
3448  Changes affecting commentary and documentation
3449
3450    Fix Tuesday/Thursday typo in description of time in Israel.
3451    (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
3452
3453    Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
3454    to Donald MacQueen.)  Instead, the Microsoft Windows Store app
3455    library supports them.
3456
3457    Add comments about Johnston Island time in the 1960s.
3458    (Thanks to Lyle McElhaney.)
3459
3460    Morocco's 2014 DST start will be as predicted.
3461    (Thanks to Sebastien Willemijns.)
3462
3463
3464Release 2014a - 2014-03-07 23:30:29 -0800
3465
3466  Changes affecting near-future timestamps
3467
3468    Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
3469    the heads-up, and to Tim Parenti for simplifying the update.)
3470
3471  Changes affecting past timestamps
3472
3473    Fiji ended DST on 2014-01-19 at 02:00, not the previously-scheduled 03:00.
3474    (Thanks to Steffen Thorsen.)
3475
3476    Ukraine switched from Moscow to Eastern European time on 1990-07-01
3477    (not 1992-01-01), and observed DST during the entire next winter.
3478    (Thanks to Vladimir in Moscow via Alois Treindl.)
3479
3480    In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
3481    (Thanks to Avigdor Finkelstein.)
3482
3483  Changes affecting code
3484
3485    A uninitialized-storage bug in 'localtime' has been fixed.
3486    (Thanks to Logan Chien.)
3487
3488  Changes affecting the build procedure
3489
3490    The settings for 'make check_web' now default to Ubuntu 13.10.
3491
3492  Changes affecting commentary and documentation
3493
3494    The boundary of the US Pacific time zone is given more accurately.
3495    (Thanks to Alan Mintz.)
3496
3497    Chile's 2014 DST will be as predicted.  (Thanks to José Miguel Garrido.)
3498
3499    Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raúl Perasso.)
3500
3501    Better descriptions of countries with same time zone history as
3502    Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
3503
3504    Several changes affect tz-link.htm, the main web page.
3505
3506      Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
3507      David Braverman).
3508
3509      Mention xCal (Internet RFC 6321) and jCal.
3510
3511      Microsoft has some support for tz database names.
3512
3513      CLDR data formats include both XML and JSON.
3514
3515      Mention Maggiolo's map of solar vs standard time.
3516      (Thanks to Arthur David Olson.)
3517
3518      Mention TZ4Net.  (Thanks to Matt Johnson.)
3519
3520      Mention the timezone-olson Haskell package.
3521
3522      Mention zeitverschiebung.net.  (Thanks to Martin Jäger.)
3523
3524      Remove moribund links to daylight-savings-time.info and to
3525      Simple Timer + Clocks.
3526
3527      Update two links.  (Thanks to Oscar van Vlijmen.)
3528
3529      Fix some formatting glitches, e.g., remove random newlines from
3530      abbr elements' title attributes.
3531
3532
3533Release 2013i - 2013-12-17 07:25:23 -0800
3534
3535  Changes affecting near-future timestamps:
3536
3537    Jordan switches back to standard time at 00:00 on December 20, 2013.
3538    The 2006-2011 transition schedule is planned to resume in 2014.
3539    (Thanks to Steffen Thorsen.)
3540
3541  Changes affecting past timestamps:
3542
3543    In 2004, Cuba began DST on March 28, not April 4.
3544    (Thanks to Steffen Thorsen.)
3545
3546  Changes affecting code
3547
3548    The compile-time flag NOSOLAR has been removed, as nowadays the
3549    benefit of slightly shrinking runtime table size is outweighed by the
3550    cost of disallowing potential future updates that exceed old limits.
3551
3552  Changes affecting documentation and commentary
3553
3554    The files solar87, solar88, and solar89 are no longer distributed.
3555    They were a negative experiment - that is, a demonstration that
3556    tz data can represent solar time only with some difficulty and error.
3557    Their presence in the distribution caused confusion, as Riyadh
3558    civil time was generally not solar time in those years.
3559
3560    tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
3561
3562
3563Release 2013h - 2013-10-25 15:32:32 -0700
3564
3565  Changes affecting current and future timestamps:
3566
3567    Libya has switched its UT offset back to +02 without DST, instead
3568    of +01 with DST.  (Thanks to Even Scharning.)
3569
3570    Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
3571    (Thanks to Gwillim Law.)
3572
3573  Changes affecting future timestamps:
3574
3575    Acre and (we guess) western Amazonas will switch from UT -04 to -05
3576    on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
3577    (Thanks to Steffen Thorsen.)
3578
3579    Add entries for DST transitions in Morocco in the year 2038.
3580    This avoids some year-2038 glitches introduced in 2013g.
3581    (Thanks to Yoshito Umaoka for reporting the problem.)
3582
3583  Changes affecting API
3584
3585    The 'tzselect' command no longer requires the 'select' command,
3586    and should now work with /bin/sh on more platforms.  It also works
3587    around a bug in BusyBox awk before version 1.21.0.  (Thanks to
3588    Patrick 'P. J.' McDermott and Alan Barrett.)
3589
3590  Changes affecting code
3591
3592    Fix localtime overflow bugs with 32-bit unsigned time_t.
3593
3594    zdump no longer assumes sscanf returns maximal values on overflow.
3595
3596  Changes affecting the build procedure
3597
3598    The builder can specify which programs to use, if any, instead of
3599    'ar' and 'ranlib', and libtz.a is now built locally before being
3600    installed.  (Thanks to Michael Forney.)
3601
3602    A dependency typo in the 'zdump' rule has been fixed.
3603    (Thanks to Andrew Paprocki.)
3604
3605    The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
3606    work as specified by POSIX.2-1992 or later; this is portable nowadays.
3607
3608    'make clean' no longer removes 'leapseconds', since it's
3609    host-independent and is part of the distribution.
3610
3611    The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
3612
3613  Changes affecting documentation and commentary
3614
3615    tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
3616    (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
3617
3618    Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
3619    8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
3620    longer maintained) and for old advisories.  SOFA now does C.
3621
3622Release 2013g - 2013-09-30 21:08:26 -0700
3623
3624  Changes affecting current and near-future timestamps
3625
3626    Morocco now observes DST from the last Sunday in March to the last
3627    Sunday in October, not April to September respectively.  (Thanks
3628    to Steffen Thorsen.)
3629
3630  Changes affecting 'zic'
3631
3632    'zic' now runs on platforms that lack both hard links and symlinks.
3633    (Thanks to Theo Veenker for reporting the problem, for MinGW.)
3634    Also, fix some bugs on platforms that lack hard links but have symlinks.
3635
3636    'zic -v' again warns that Asia/Tehran has no POSIX environment variable
3637    to predict the far future, fixing a bug introduced in 2013e.
3638
3639  Changes affecting the build procedure
3640
3641    The 'leapseconds' file is again put into the tzdata tarball.
3642    Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
3643    Matt Burgess and Ian Abbott.)  The timestamps of these and other
3644    dependent files in tarballs are adjusted more consistently.
3645
3646  Changes affecting documentation and commentary
3647
3648    The README file is now part of the data tarball as well as the code.
3649    It now states that files are public domain unless otherwise specified.
3650    (Thanks to Andrew Main (Zefram) for asking for clarifications.)
3651    Its details about the 1989 release moved to a place of honor near
3652    the end of NEWS.
3653
3654
3655Release 2013f - 2013-09-24 23:37:36 -0700
3656
3657  Changes affecting near-future timestamps
3658
3659    Tocantins will very likely not observe DST starting this spring.
3660    (Thanks to Steffen Thorsen.)
3661
3662    Jordan will likely stay at UT +03 indefinitely, and will not fall
3663    back this fall.
3664
3665    Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
3666
3667  Changes affecting API
3668
3669    The types of the global variables 'timezone' and 'altzone' (if present)
3670    have been changed back to 'long'.  This is required for 'timezone'
3671    by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
3672    These variables were originally 'long' in the tz code, but were
3673    mistakenly changed to 'time_t' in 1987; nobody reported the
3674    incompatibility until now.  The difference matters on x32, where
3675    'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
3676
3677  Changes affecting the build procedure
3678
3679    Avoid long strings in leapseconds.awk to work around a mawk bug.
3680    (Thanks to Cyril Baurand.)
3681
3682  Changes affecting documentation and commentary
3683
3684    New file 'NEWS' that contains release notes like this one.
3685
3686    Paraguay's law does not specify DST transition time; 00:00 is customary.
3687    (Thanks to Waldemar Villamayor-Venialbo.)
3688
3689    Minor capitalization fixes.
3690
3691  Changes affecting version-control only
3692
3693    The experimental GitHub repository now contains annotated and
3694    signed tags for recent releases, e.g., '2013e' for Release 2013e.
3695    Releases are tagged starting with 2012e; earlier releases were
3696    done differently, and tags would either not have a simple name or
3697    not exactly match what was released.
3698
3699    'make set-timestamps' is now simpler and a bit more portable.
3700
3701
3702Release 2013e - 2013-09-19 23:50:04 -0700
3703
3704  Changes affecting near-future timestamps
3705
3706    This year Fiji will start DST on October 27, not October 20.
3707    (Thanks to David Wheeler for the heads-up.)  For now, guess that
3708    Fiji will continue to spring forward the Sunday before the fourth
3709    Monday in October.
3710
3711  Changes affecting current and future time zone abbreviations
3712
3713    Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
3714    time zone abbreviations since 1932.  (Thanks to George Ziegler,
3715    Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
3716    Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
3717    Asia/Makassar, and Asia/Pontianak.
3718
3719    Use ART (UT -03, standard time), rather than WARST (also -03, but
3720    daylight saving time) for San Luis, Argentina since 2009.
3721
3722  Changes affecting Godthåb timestamps after 2037 if version mismatch
3723
3724    Allow POSIX-like TZ strings where the transition time's hour can
3725    range from -167 through 167, instead of the POSIX-required 0
3726    through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
3727    new Fiji rules.  This is a more-compact way to represent
3728    far-future timestamps for America/Godthab, America/Santiago,
3729    Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
3730    Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
3731    this change.  (Derived from a suggestion by Arthur David Olson.)
3732
3733    Allow POSIX-like TZ strings where daylight saving time is in
3734    effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
3735    Argentina Summer Time all year.  This supports a more-compact way
3736    to represent the 2013d data for America/Argentina/San_Luis.
3737    Because of the change for San Luis noted above this change does not
3738    affect the current data.  (Thanks to Andrew Main (Zefram) for
3739    suggestions that improved this change.)
3740
3741    Where these two TZ changes take effect, there is a minor extension
3742    to the tz file format in that it allows new values for the
3743    embedded TZ-format string, and the tz file format version number
3744    has therefore been increased from 2 to 3 as a precaution.
3745    Version-2-based client code should continue to work as before for
3746    all timestamps before 2038.  Existing version-2-based client code
3747    (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
3748    files, and typically works in practice even for timestamps after
3749    2037; the only known exception is America/Godthab.
3750
3751  Changes affecting timestamps before 1970
3752
3753    Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
3754    some errors before 1947.
3755
3756    Some zones have been turned into links, when they differ from existing
3757    zones only in older data entries that were likely invented or that
3758    differ only in LMT or transitions from LMT.  These changes affect
3759    only timestamps before 1943.  The affected zones are:
3760    Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
3761    America/Grenada, America/Guadeloupe, America/Marigot,
3762    America/Montserrat, America/St_Barthelemy, America/St_Kitts,
3763    America/St_Lucia, America/St_Thomas, America/St_Vincent,
3764    America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
3765    confirming that the old Europe/Vaduz zone was wrong and the new
3766    link is better for WWII-era times.)
3767
3768    Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
3769    America/Cayman, America/Jamaica and America/Grand_Turk timestamps
3770    from 1890 to 1912.
3771
3772    Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
3773    This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
3774    to Alois Treindl.)
3775
3776    Change the date of the circa-1850 Zurich transition from 1849-09-12
3777    to 1853-07-16, overriding Shanks with data from Messerli about
3778    postal and telegraph time in Switzerland.
3779
3780  Changes affecting time zone abbreviations before 1970
3781
3782    For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
3783    as Jakarta was called Batavia back then.
3784
3785  Changes affecting API
3786
3787    The 'zic' command now outputs a dummy transition when far-future
3788    data can't be summarized using a TZ string, and uses a 402-year
3789    window rather than a 400-year window.  For the current data, this
3790    affects only the Asia/Tehran file.  It does not affect any of the
3791    timestamps that this file represents, so zdump outputs the same
3792    information as before.  (Thanks to Andrew Main (Zefram).)
3793
3794    The 'date' command has a new '-r' option, which lets you specify
3795    the integer time to display, a la FreeBSD.
3796
3797    The 'tzselect' command has two new options '-c' and '-n', which lets you
3798    select a zone based on latitude and longitude.
3799
3800    The 'zic' command's '-v' option now warns about constructs that
3801    require the new version-3 binary file format.  (Thanks to Arthur
3802    David Olson for the suggestion.)
3803
3804    Support for floating-point time_t has been removed.
3805    It was always dicey, and POSIX no longer requires it.
3806    (Thanks to Eric Blake for suggesting to the POSIX committee to
3807    remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
3808    Heninger, Arthur David Olson, and Alois Treindl, for reporting
3809    bugs and elucidating some of the corners of the old floating-point
3810    implementation.)
3811
3812    The signatures of 'offtime', 'timeoff', and 'gtime' have been
3813    changed back to the old practice of using 'long' to represent UT
3814    offsets.  This had been inadvertently and mistakenly changed to
3815    'int_fast32_t'.  (Thanks to Christos Zoulas.)
3816
3817    The code avoids undefined behavior on integer overflow in some
3818    more places, including gmtime, localtime, mktime and zdump.
3819
3820  Changes affecting the zdump utility
3821
3822    zdump now outputs "UT" when referring to Universal Time, not "UTC".
3823    "UTC" does not make sense for timestamps that predate the introduction
3824    of UTC, whereas "UT", a more-generic term, does.  (Thanks to Steve Allen
3825    for clarifying UT vs UTC.)
3826
3827  Data changes affecting behavior of tzselect and similar programs
3828
3829    Country code BQ is now called the more-common name "Caribbean Netherlands"
3830    rather than the more-official "Bonaire, St Eustatius & Saba".
3831
3832    Remove from zone.tab the names America/Montreal, America/Shiprock,
3833    and Antarctica/South_Pole, as they are equivalent to existing
3834    same-country-code zones for post-1970 timestamps.  The data entries for
3835    these names are unchanged, so the names continue to work as before.
3836
3837  Changes affecting code internals
3838
3839    zic -c now runs way faster on 64-bit hosts when given large numbers.
3840
3841    zic now uses vfprintf to avoid allocating and freeing some memory.
3842
3843    tzselect now computes the list of continents from the data,
3844    rather than have it hard-coded.
3845
3846    Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
3847
3848  Changes affecting the build procedure
3849
3850    The 'leapseconds' file is now generated automatically from a
3851    new file 'leap-seconds.list', which is a copy of
3852    <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
3853    A new source file 'leapseconds.awk' implements this.
3854    The goal is simplification of the future maintenance of 'leapseconds'.
3855
3856    When building the 'posix' or 'right' subdirectories, if the
3857    subdirectory would be a copy of the default subdirectory, it is
3858    now made a symbolic link if that is supported.  This saves about
3859    2 MB of file system space.
3860
3861    The links America/Shiprock and Antarctica/South_Pole have been
3862    moved to the 'backward' file.  This affects only nondefault builds
3863    that omit 'backward'.
3864
3865  Changes affecting version-control only
3866
3867    .gitignore now ignores 'date'.
3868
3869  Changes affecting documentation and commentary
3870
3871    Changes to the 'tzfile' man page
3872
3873      It now mentions that the binary file format may be extended in
3874      future versions by appending data.
3875
3876      It now refers to the 'zdump' and 'zic' man pages.
3877
3878    Changes to the 'zic' man page
3879
3880      It lists conditions that elicit a warning with '-v'.
3881
3882      It says that the behavior is unspecified when duplicate names
3883      are given, or if the source of one link is the target of another.
3884
3885      Its examples are updated to match the latest data.
3886
3887      The definition of white space has been clarified slightly.
3888      (Thanks to Michael Deckers.)
3889
3890    Changes to the 'Theory' file
3891
3892      There is a new section about the accuracy of the tz database,
3893      describing the many ways that errors can creep in, and
3894      explaining why so many of the pre-1970 timestamps are wrong or
3895      misleading (thanks to Steve Allen, Lester Caine, and Garrett
3896      Wollman for discussions that contributed to this).
3897
3898      The 'Theory' file describes LMT better (this follows a
3899      suggestion by Guy Harris).
3900
3901      It refers to the 2013 edition of POSIX rather than the 2004 edition.
3902
3903      It's mentioned that excluding 'backward' should not affect the
3904      other data, and it suggests at least one zone.tab name per
3905      inhabited country (thanks to Stephen Colebourne).
3906
3907      Some longstanding restrictions on names are documented, e.g.,
3908      'America/New_York' precludes 'America/New_York/Bronx'.
3909
3910      It gives more reasons for the 1970 cutoff.
3911
3912      It now mentions which time_t variants are supported, such as
3913      signed integer time_t.  (Thanks to Paul Goyette for reporting
3914      typos in an experimental version of this change.)
3915
3916      (Thanks to Philip Newton for correcting typos in these changes.)
3917
3918    Documentation and commentary is more careful to distinguish UT in
3919    general from UTC in particular.  (Thanks to Steve Allen.)
3920
3921    Add a better source for the Zurich 1894 transition.
3922    (Thanks to Pierre-Yves Berger.)
3923
3924    Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
3925
3926
3927Release 2013d - 2013-07-05 07:38:01 -0700
3928
3929  Changes affecting future timestamps:
3930
3931    Morocco's midsummer transitions this year are July 7 and August 10,
3932    not July 9 and August 8.  (Thanks to Andrew Paprocki.)
3933
3934    Israel now falls back on the last Sunday of October.
3935    (Thanks to Ephraim Silverberg.)
3936
3937  Changes affecting past timestamps:
3938
3939    Specify Jerusalem's location more precisely; this changes the pre-1880
3940    times by 2 s.
3941
3942  Changing affecting metadata only:
3943
3944    Fix typos in the entries for country codes BQ and SX.
3945
3946  Changes affecting code:
3947
3948    Rework the code to fix a bug with handling Australia/Macquarie on
3949    32-bit hosts (thanks to Arthur David Olson).
3950
3951    Port to platforms like NetBSD, where time_t can be wider than long.
3952
3953    Add support for testing time_t types other than the system's.
3954    Run 'make check_time_t_alternatives' to try this out.
3955    Currently, the tests fail for unsigned time_t;
3956    this should get fixed at some point.
3957
3958  Changes affecting documentation and commentary:
3959
3960    Deemphasize the significance of national borders.
3961
3962    Update the zdump man page.
3963
3964    Remove obsolete NOID comment (thanks to Denis Excoffier).
3965
3966    Update several URLs and comments in the web pages.
3967
3968    Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
3969
3970    Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
3971
3972
3973Release 2013c - 2013-04-19 16:17:40 -0700
3974
3975  Changes affecting current and future timestamps:
3976
3977    Palestine observed DST starting March 29, 2013.  (Thanks to
3978    Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
3979    with the predicted rules being the last Thursday in March at 24:00
3980    to the first Friday on or after September 21 at 01:00.
3981
3982    Assume that the recent change to Paraguay's DST rules is permanent,
3983    by moving the end of DST to the 4th Sunday in March every year.
3984    (Thanks to Carlos Raúl Perasso.)
3985
3986  Changes affecting past timestamps:
3987
3988    Fix some historical data for Palestine to agree with that of
3989    timeanddate.com, as follows:
3990
3991	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
3992	  00:00 Apr 1.
3993
3994	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
3995	  02:00.
3996
3997	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
3998
3999	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
4000
4001	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
4002
4003	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
4004
4005    Fix times of habitation for Macquarie to agree with the Tasmania
4006    Parks & Wildlife Service history, which indicates that permanent
4007    habitation was 1899-1919 and 1948 on.
4008
4009  Changing affecting metadata only:
4010
4011    Macquarie Island is politically part of Australia, not Antarctica.
4012    (Thanks to Tobias Conradi.)
4013
4014    Sort Macquarie more-consistently with other parts of Australia.
4015    (Thanks to Tim Parenti.)
4016
4017
4018Release 2013b - 2013-03-10 22:33:40 -0700
4019
4020  Changes affecting current and future timestamps:
4021
4022    Haiti uses US daylight-saving rules this year, and presumably future years.
4023    This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
4024
4025    Paraguay will end DST on March 24 this year.
4026    (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
4027
4028    Morocco does not observe DST during Ramadan;
4029    try to predict Ramadan in Morocco as best we can.
4030    (Thanks to Erik Homoet for the heads-up.)
4031
4032  Changes affecting commentary:
4033
4034    Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
4035    Update URL for Solaris.  Mention Internet RFC 6557.
4036    Update Internet RFCs 2445->5545, 2822->5322.
4037    Switch from FTP to HTTP for Internet RFCs.
4038
4039
4040Release 2013a - 2013-02-27 09:20:35 -0800
4041
4042  Change affecting binary data format:
4043
4044    The zone offset at the end of version-2-format zone files is now
4045    allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
4046
4047  Changes affecting current and future timestamps:
4048
4049    Chile's 2013 rules, and we guess rules for 2014 and later, will be
4050    the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
4051    (Thanks to Steffen Thorsen and Robert Elz.)
4052
4053    New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
4054    (Thanks to Tobias Conradi and Arthur David Olson.)
4055
4056  Many changes affect historical timestamps before 1940.
4057  These were deduced from: Milne J. Civil time. Geogr J. 1899
4058  Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
4059
4060  Changes affecting the code:
4061
4062    Fix zic bug that mishandled Egypt's 2010 changes (this also affected
4063    the data).  (Thanks to Arthur David Olson.)
4064
4065    Fix localtime bug when time_t is unsigned and data files were generated
4066    by a signed time_t system.  (Thanks to Doug Bailey for reporting and
4067    to Arthur David Olson for fixing.)
4068
4069    Allow the email address for bug reports to be set by the packager.
4070    The default is tz@iana.org, as before.  (Thanks to Joseph S. Myers.)
4071
4072    Update HTML checking to be compatible with Ubuntu 12.10.
4073
4074    Check that files are a safe subset of ASCII.  At some point we may
4075    relax this requirement to a safe subset of UTF-8.  Without the
4076    check, some non-UTF-8 encodings were leaking into the distribution.
4077
4078  Commentary changes:
4079
4080    Restore a comment about copyright notices that was inadvertently deleted.
4081    (Thanks to Arthur David Olson.)
4082
4083    Improve the commentary about which districts observe what times
4084    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
4085
4086    Add web page links to tz.js.
4087
4088    Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
4089
4090
4091Release 2012j - 2012-11-12 18:34:49 -0800
4092
4093  Libya moved to CET this weekend, but with DST planned next year.
4094  (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
4095
4096  Signatures now have the extension .asc, not .sign, as that's more
4097  standard.  (Thanks to Phil Pennock.)
4098
4099  The output of 'zdump --version', and of 'zic --version', now
4100  uses a format that is more typical for --version.
4101  (Thanks to Joseph S. Myers.)
4102
4103  The output of 'tzselect --help', 'zdump --help', and 'zic --help'
4104  now uses tz@iana.org rather than the old elsie address.
4105
4106  zic -v now complains about abbreviations that are less than 3
4107  or more than 6 characters, as per Posix.  Formerly, it checked
4108  for abbreviations that were more than 3.
4109
4110  'make public' no longer puts its temporary directory under /tmp,
4111  and uses the just-built zic rather than the system zic.
4112
4113  Various fixes to documentation and commentary.
4114
4115
4116Release 2012i - 2012-11-03 12:57:09 -0700
4117
4118  Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
4119
4120  Linker flags can now be specified via LDFLAGS.
4121  AWK now defaults to 'awk', not 'nawk'.
4122  The shell in tzselect now defaults to /bin/bash, but this can
4123  be overridden by specifying KSHELL.
4124  The main web page now mentions the unofficial GitHub repository.
4125  (Thanks to Mike Frysinger.)
4126
4127  Tarball signatures can now be built by running 'make signatures'.
4128  There are also new makefile rules 'tarballs', 'check_public', and
4129  separate makefile rules for each tarball and signature file.
4130  A few makefile rules are now more portable to strict POSIX.
4131
4132  The main web page now lists the canonical IANA URL.
4133
4134
4135Release 2012h - 2012-10-26 22:49:10 -0700
4136
4137  Bahia no longer has DST.  (Thanks to Kelley Cook.)
4138
4139  Tocantins has DST.  (Thanks to Rodrigo Severo.)
4140
4141  Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
4142
4143  Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
4144
4145  Web page updates.
4146
4147  More C modernization, except that at Arthur David Olson's suggestion
4148  the instances of 'register' were kept.
4149
4150
4151Release 2012g - 2012-10-17 20:59:45 -0700
4152
4153  Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
4154
4155  Palestine fall 2012.  (Thanks to Steffen Thorsen.)
4156
4157  Assume C89.
4158
4159  To attack the version-number problem, this release ships the file
4160  'Makefile' (which contains the release number) in both the tzcode and
4161  the tzdata tarballs.  The two Makefiles are identical, and should be
4162  identical in any matching pair of tarballs, so it shouldn't matter
4163  which order you extract the tarballs.  Perhaps we can come up with a
4164  better version-number scheme at some point; this scheme does have the
4165  virtue of not adding more files.
4166
4167
4168Release 2012f - 2012-09-12 23:17:03 -0700
4169
4170  * australasia (Pacific/Fiji): Fiji DST is October 21 through January
4171    20 this year.  (Thanks to Steffen Thorsen.)
4172
4173
4174Release 2012e - 2012-08-02 20:44:55 -0700
4175
4176  * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
4177    (Thanks to Steffen Thorsen.)
4178
4179  * Use a single version number for both code and data.
4180
4181  * .gitignore: New file.
4182
4183  * Remove trailing white space.
4184
4185
4186Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
4187
4188  Changes for Morocco's timestamps, which take effect in a couple of
4189  hours, along with infrastructure changes to accommodate how the tz
4190  code and data are released on IANA.
4191
4192
4193Release data2012c - 2012-03-27 12:17:25 -0400
4194
4195  africa
4196	Summer time changes for Morocco (to start late April 2012)
4197
4198  asia
4199	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
4200
4201  northamerica
4202	Haiti following US/Canada rules for 2012 (and we're assuming,
4203	for now anyway, for the future).
4204
4205
4206Release 2012b - 2012-03-02 12:29:15 +0700
4207
4208  There is just one change to tzcode2012b (compared with 2012a):
4209  the Makefile that was accidentally included with 2012a has been
4210  replaced with the version that should have been there, which is
4211  identical with the previous version (from tzcode2011i).
4212
4213  There are just two changes in tzdata2012b compared with 2012a.
4214
4215  Most significantly, summer time in Cuba has been delayed 3 weeks
4216  (now starts April 1 rather than March 11).   Since Mar 11 (the old start
4217  date, as listed in 2012a) is just a little over a week away, this
4218  change is urgent.
4219
4220  Less importantly, an excess tab in one of the changes in zone.tab
4221  in 2012a has been removed.
4222
4223
4224Release 2012a - 2012-03-01 18:28:10 +0700
4225
4226  The changes in tzcode2012a (compared to the previous version, 2011i)
4227  are entirely to the README and tz-art.htm and tz-link.htm files, if
4228  none of those concern you, you can ignore the code update.  The changes
4229  reflect the changed addresses for the mailing list and the code and
4230  data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
4231  has been added to tz-link.htm).
4232
4233  In tzdata2012a (compared to the previous release, which was 2011n)
4234  the major changes are:
4235	Chile 2011/2012 and 2012/2013 summer time date adjustments.
4236	Falkland Islands onto permanent summer time (we're assuming for the
4237		foreseeable future, though 2012 is all we're fairly certain of.)
4238	Armenia has abolished Summer Time.
4239	Tokelau jumped the International Date Line back last December
4240		(just the same as their near neighbour, Samoa).
4241	America/Creston is a new zone for a small area of British Columbia
4242	There will be a leapsecond 2012-06-30 23:59:60 UTC.
4243
4244  Other minor changes are:
4245	Corrections to 1918 Canadian summer time end dates.
4246	Updated URL for UK time zone history (in comments)
4247	A few typos in Le Corre's list of free French place names (comments)
4248
4249
4250Release data2011n - 2011-10-30 14:57:54 +0700
4251
4252  There are three changes of note - most urgently, Cuba (America/Havana)
4253  has extended summer time by two weeks, now to end on Nov 13, rather than
4254  the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
4255  (Europe/Tiraspol) decided not to split from the rest of Moldova after
4256  all, and consequently that zone has been removed (again) and reinstated
4257  in the "backward" file as a link to Europe/Chisinau.   And third, the
4258  end date for Fiji's summer time this summer was moved forward from the
4259  earlier planned Feb 26, to Jan 22.
4260
4261  Apart from that, Moldova (MD) returns to a single entry in zone.tab
4262  (and the incorrect syntax that was in the 2011m version of that file
4263  is so fixed - it would have been fixed in a different way had this
4264  change not happened - that's the "missing" sccs version id).
4265
4266
4267Release data2011m - 2011-10-24 21:42:16 +0700
4268
4269  In particular, the typos in comments in the data (2011-11-17 should have
4270  been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
4271  Tim Parenti noted) have been fixed, and the change for Ukraine has been
4272  made in all 4 Ukrainian zones, rather than just Kiev (again, thanks to
4273  Tim Parenti, and also Denys Gavrysh)
4274
4275  In addition, I added Europe/Tiraspol to zone.tab.
4276
4277  This time, all the files have new version numbers...  (including the files
4278  otherwise unchanged in 2011m that were changed in 2011l but didn't get new
4279  version numbers there...)
4280
4281
4282Release data2011l - 2011-10-10 11:15:43 +0700
4283
4284  There are just 2 changes that cause different generated tzdata files from
4285  zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
4286  is included, but commented out.  Compared with the diff I sent out last week,
4287  this version also includes attributions for the sources for the changes
4288  (in much the same format as ado used, but the html tags have not been
4289  checked, verified, or used in any way at all, so if there are errors there,
4290  please let me know.)
4291
4292
4293Release data2011k - 2011-09-20 17:54:03 -0400
4294
4295  [not summarized]
4296
4297
4298Release data2011j - 2011-09-12 09:22:49 -0400
4299
4300  (contemporary changes for Samoa; past changes for Kenya, Uganda, and
4301  Tanzania); there are also two spelling corrections to comments in
4302  the australasia file (with thanks to Christos Zoulas).
4303
4304
4305Release 2011i - 2011-08-29 05:56:32 -0400
4306
4307  [not summarized]
4308
4309
4310Release data2011h - 2011-06-15 18:41:48 -0400
4311
4312  Russia and Curaçao changes
4313
4314
4315Release 2011g - 2011-04-25 09:07:22 -0400
4316
4317  update the rules for Egypt to reflect its abandonment of DST this year
4318
4319
4320Release 2011f - 2011-04-06 17:14:53 -0400
4321
4322  [not summarized]
4323
4324
4325Release 2011e - 2011-03-31 16:04:38 -0400
4326
4327  Morocco, Chile, and tz-link changes
4328
4329
4330Release 2011d - 2011-03-14 09:18:01 -0400
4331
4332  changes that impact present-day timestamps in Cuba, Samoa, and Turkey
4333
4334
4335Release 2011c - 2011-03-07 09:30:09 -0500
4336
4337  These do affect current timestamps in Chile and Annette Island, Canada.
4338
4339
4340Release 2011b - 2011-02-07 08:44:50 -0500
4341
4342  [not summarized]
4343
4344
4345Release 2011a - 2011-01-24 10:30:16 -0500
4346
4347  [not summarized]
4348
4349
4350Release data2010o - 2010-11-01 09:18:23 -0400
4351
4352  change to the end of DST in Fiji in 2011
4353
4354
4355Release 2010n - 2010-10-25 08:19:17 -0400
4356
4357  [not summarized]
4358
4359
4360Release 2010m - 2010-09-27 09:24:48 -0400
4361
4362  Hong Kong, Vostok, and zic.c changes
4363
4364
4365Release 2010l - 2010-08-16 06:57:25 -0400
4366
4367  [not summarized]
4368
4369
4370Release 2010k - 2010-07-26 10:42:27 -0400
4371
4372  [not summarized]
4373
4374
4375Release 2010j - 2010-05-10 09:07:48 -0400
4376
4377  changes for Bahía de Banderas and for version naming
4378
4379
4380Release data2010i - 2010-04-16 18:50:45 -0400
4381
4382  the end of DST in Morocco on 2010-08-08
4383
4384
4385Release data2010h - 2010-04-05 09:58:56 -0400
4386
4387  [not summarized]
4388
4389
4390Release data2010g - 2010-03-24 11:14:53 -0400
4391
4392  [not summarized]
4393
4394
4395Release 2010f - 2010-03-22 09:45:46 -0400
4396
4397  [not summarized]
4398
4399
4400Release data2010e - 2010-03-08 14:24:27 -0500
4401
4402  corrects the Dhaka bug found by Danvin Ruangchan
4403
4404
4405Release data2010d - 2010-03-06 07:26:01 -0500
4406
4407  [not summarized]
4408
4409
4410Release 2010c - 2010-03-01 09:20:58 -0500
4411
4412  changes including KRE's suggestion for earlier initialization of
4413  "goahead" and "goback" structure elements
4414
4415
4416Release code2010a - 2010-02-16 10:40:04 -0500
4417
4418  [not summarized]
4419
4420
4421Release data2010b - 2010-01-20 12:37:01 -0500
4422
4423  Mexico changes
4424
4425
4426Release data2010a - 2010-01-18 08:30:04 -0500
4427
4428  changes to Dhaka
4429
4430
4431Release data2009u - 2009-12-26 08:32:28 -0500
4432
4433  changes to DST in Bangladesh
4434
4435
4436Release 2009t - 2009-12-21 13:24:27 -0500
4437
4438  [not summarized]
4439
4440
4441Release data2009s - 2009-11-14 10:26:32 -0500
4442
4443  (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
4444
4445
4446Release 2009r - 2009-11-09 10:10:31 -0500
4447
4448  "antarctica" and "tz-link.htm" changes
4449
4450
4451Release 2009q - 2009-11-02 09:12:40 -0500
4452
4453  with two corrections as reported by Eric Muller and Philip Newton
4454
4455
4456Release data2009p - 2009-10-23 15:05:27 -0400
4457
4458  Argentina (including San Luis) changes (with the correction from
4459  Mariano Absatz)
4460
4461
4462Release data2009o - 2009-10-14 16:49:38 -0400
4463
4464  Samoa (commentary only), Pakistan, and Bangladesh changes
4465
4466
4467Release data2009n - 2009-09-22 15:13:38 -0400
4468
4469  added commentary for Argentina and a change to the end of DST in
4470  2009 in Pakistan
4471
4472
4473Release data2009m - 2009-09-03 10:23:43 -0400
4474
4475  Samoa and Palestine changes
4476
4477
4478Release data2009l - 2009-08-14 09:13:07 -0400
4479
4480  Samoa (comments only) and Egypt
4481
4482
4483Release 2009k - 2009-07-20 09:46:08 -0400
4484
4485  [not summarized]
4486
4487
4488Release data2009j - 2009-06-15 06:43:59 -0400
4489
4490  Bangladesh change (with a short turnaround since the DST change is
4491  impending)
4492
4493
4494Release 2009i - 2009-06-08 09:21:22 -0400
4495
4496  updating for DST in Bangladesh this year
4497
4498
4499Release 2009h - 2009-05-26 09:19:14 -0400
4500
4501  [not summarized]
4502
4503
4504Release data2009g - 2009-04-20 16:34:07 -0400
4505
4506  Cairo
4507
4508
4509Release data2009f - 2009-04-10 11:00:52 -0400
4510
4511  correct DST in Pakistan
4512
4513
4514Release 2009e - 2009-04-06 09:08:11 -0400
4515
4516  [not summarized]
4517
4518
4519Release 2009d - 2009-03-23 09:38:12 -0400
4520
4521  Morocco, Tunisia, Argentina, and American Astronomical Society changes
4522
4523
4524Release data2009c - 2009-03-16 09:47:51 -0400
4525
4526  change to the start of Cuban DST
4527
4528
4529Release 2009b - 2009-02-09 11:15:22 -0500
4530
4531  [not summarized]
4532
4533
4534Release 2009a - 2009-01-21 10:09:39 -0500
4535
4536  [not summarized]
4537
4538
4539Release data2008i - 2008-10-21 12:10:25 -0400
4540
4541  southamerica and zone.tab files, with Argentina DST rule changes and
4542  United States zone reordering and recommenting
4543
4544
4545Release 2008h - 2008-10-13 07:33:56 -0400
4546
4547  [not summarized]
4548
4549
4550Release 2008g - 2008-10-06 09:03:18 -0400
4551
4552  Fix a broken HTML anchor and update Brazil's DST transitions;
4553  there's also a slight reordering of information in tz-art.htm.
4554
4555
4556Release data2008f - 2008-09-09 22:33:26 -0400
4557
4558  [not summarized]
4559
4560
4561Release 2008e - 2008-07-28 14:11:17 -0400
4562
4563  changes by Arthur David Olson and Jesper Nørgaard Welen
4564
4565
4566Release data2008d - 2008-07-07 09:51:38 -0400
4567
4568  changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
4569
4570
4571Release data2008c - 2008-05-19 17:48:03 -0400
4572
4573  Pakistan, Morocco, and Mongolia
4574
4575
4576Release data2008b - 2008-03-24 08:30:59 -0400
4577
4578  including renaming Asia/Calcutta to Asia/Kolkata, with a backward
4579  link provided
4580
4581
4582Release 2008a - 2008-03-08 05:42:16 -0500
4583
4584  [not summarized]
4585
4586
4587Release 2007k - 2007-12-31 10:25:22 -0500
4588
4589  most importantly, changes to the "southamerica" file based on
4590  Argentina's readoption of daylight saving time
4591
4592
4593Release 2007j - 2007-12-03 09:51:01 -0500
4594
4595  1. eliminate the "P" (parameter) macro;
4596
4597  2. the "noncontroversial" changes circulated on the time zone
4598  mailing list (less the changes to "logwtmp.c");
4599
4600  3. eliminate "too many transition" errors when "min" is used in time
4601  zone rules;
4602
4603  4. changes by Paul Eggert (including updated information for Venezuela).
4604
4605
4606Release data2007i - 2007-10-30 10:28:11 -0400
4607
4608  changes for Cuba and Syria
4609
4610
4611Release 2007h - 2007-10-01 10:05:51 -0400
4612
4613  changes by Paul Eggert, as well as an updated link to the ICU
4614  project in tz-link.htm
4615
4616
4617Release 2007g - 2007-08-20 10:47:59 -0400
4618
4619  changes by Paul Eggert
4620
4621  The "leapseconds" file has been updated to incorporate the most
4622  recent International Earth Rotation and Reference Systems Service
4623  (IERS) bulletin.
4624
4625  There's an addition to tz-art.htm regarding the television show "Medium".
4626
4627
4628Release 2007f - 2007-05-07 10:46:46 -0400
4629
4630  changes by Paul Eggert (including Haiti, Turks and Caicos, and New
4631  Zealand)
4632
4633  changes to zic.c to allow hour values greater than 24 (along with
4634  Paul's improved time value overflow checking)
4635
4636
4637Release 2007e - 2007-04-02 10:11:52 -0400
4638
4639  Syria and Honduras changes by Paul Eggert
4640
4641  zic.c variable renaming changes by Arthur David Olson
4642
4643
4644Release 2007d - 2007-03-20 08:48:30 -0400
4645
4646  changes by Paul Eggert
4647
4648  the elimination of white space at the ends of lines
4649
4650
4651Release 2007c - 2007-02-26 09:09:37 -0500
4652
4653  changes by Paul Eggert
4654
4655
4656Release 2007b - 2007-02-12 09:34:20 -0500
4657
4658  Paul Eggert's proposed change to the quotation handling logic in zic.c.
4659
4660  changes to the commentary in "leapseconds" reflecting the IERS
4661  announcement that there is to be no positive leap second at the end
4662  of June 2007.
4663
4664
4665Release 2007a - 2007-01-08 12:28:29 -0500
4666
4667  changes by Paul Eggert
4668
4669  Derick Rethans's Asmara change
4670
4671  Oscar van Vlijmen's Easter Island local mean time change
4672
4673  symbolic link changes
4674
4675
4676Release 2006p - 2006-11-27 08:54:27 -0500
4677
4678  changes by Paul Eggert
4679
4680
4681Release 2006o - 2006-11-06 09:18:07 -0500
4682
4683  changes by Paul Eggert
4684
4685
4686Release 2006n - 2006-10-10 11:32:06 -0400
4687
4688  changes by Paul Eggert
4689
4690
4691Release 2006m - 2006-10-02 15:32:35 -0400
4692
4693  changes for Uruguay, Palestine, and Egypt by Paul Eggert
4694
4695  (minimalist) changes to zic.8 to clarify "until" information
4696
4697
4698Release data2006l - 2006-09-18 12:58:11 -0400
4699
4700  Paul's best-effort work on this coming weekend's Egypt time change
4701
4702
4703Release 2006k - 2006-08-28 12:19:09 -0400
4704
4705  changes by Paul Eggert
4706
4707
4708Release 2006j - 2006-08-21 09:56:32 -0400
4709
4710  changes by Paul Eggert
4711
4712
4713Release code2006i - 2006-08-07 12:30:55 -0400
4714
4715  localtime.c fixes
4716
4717  Ken Pizzini's conversion script
4718
4719
4720Release code2006h - 2006-07-24 09:19:37 -0400
4721
4722  adds public domain notices to four files
4723
4724  includes a fix for transition times being off by a second
4725
4726  adds a new recording to the "arts" file (information courtesy Colin Bowern)
4727
4728
4729Release 2006g - 2006-05-08 17:18:09 -0400
4730
4731  northamerica changes by Paul Eggert
4732
4733
4734Release 2006f - 2006-05-01 11:46:00 -0400
4735
4736  a missing version number problem is fixed (with thanks to Bradley
4737  White for catching the problem)
4738
4739
4740Release 2006d - 2006-04-17 14:33:43 -0400
4741
4742  changes by Paul Eggert
4743
4744  added new items to tz-arts.htm that were found by Paul
4745
4746
4747Release 2006c - 2006-04-03 10:09:32 -0400
4748
4749  two sets of data changes by Paul Eggert
4750
4751  a fencepost error fix in zic.c
4752
4753  changes to zic.c and the "europe" file to minimize differences
4754  between output produced by the old 32-bit zic and the new 64-bit
4755  version
4756
4757
4758Release 2006b - 2006-02-20 10:08:18 -0500
4759  [tz32code2006b + tz64code2006b + tzdata2006b]
4760
4761  64-bit code
4762
4763  All SCCS IDs were bumped to "8.1" for this release.
4764
4765
4766Release 2006a - 2006-01-30 08:59:31 -0500
4767
4768  changes by Paul Eggert (in particular, Indiana time zone moves)
4769
4770  an addition to the zic manual page to describe how special-case
4771  transitions are handled
4772
4773
4774Release 2005r - 2005-12-27 09:27:13 -0500
4775
4776  Canadian changes by Paul Eggert
4777
4778  They also add "<pre>" directives to time zone data files and reflect
4779  changes to warning message logic in "zdump.c" (but with calls to
4780  "gettext" kept unbundled at the suggestion of Ken Pizzini).
4781
4782
4783Release 2005q - 2005-12-13 09:17:09 -0500
4784
4785  Nothing earth-shaking here:
4786	1.  Electronic mail addresses have been removed.
4787	2.  Casts of the return value of exit have been removed.
4788	3.  Casts of the argument of is.* macros have been added.
4789	4.  Indentation in one section of zic.c has been fixed.
4790	5.  References to dead URLs in the data files have been dealt with.
4791
4792
4793Release 2005p - 2005-12-05 10:30:53 -0500
4794
4795  "systemv", "tz-link.htm", and "zdump.c" changes
4796  (less the casts of arguments to the is* macros)
4797
4798
4799Release 2005o - 2005-11-28 10:55:26 -0500
4800
4801  Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
4802
4803  zdump.c lint fixes by Arthur David Olson
4804
4805
4806Release 2005n - 2005-10-03 09:44:09 -0400
4807
4808  changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
4809  et al. changes)
4810
4811
4812Release 2005m - 2005-08-29 12:15:40 -0400
4813
4814  changes by Paul Eggert (with a small tweak to the tz-art change)
4815
4816  a declaration of an unused variable has been removed from zdump.c
4817
4818
4819Release 2005l - 2005-08-22 12:06:39 -0400
4820
4821  changes by Paul Eggert
4822
4823  overflow/underflow checks by Arthur David Olson, minus changes to
4824  the "Theory" file about the pending addition of 64-bit data (I grow
4825  less confident of the changes being accepted with each passing day,
4826  and the changes no longer increase the data files nine-fold--there's
4827  less than a doubling in size by my local Sun's reckoning)
4828
4829
4830Release 2005k - 2005-07-14 14:14:24 -0400
4831
4832  The "leapseconds" file has been edited to reflect the recently
4833  announced leap second at the end of 2005.
4834
4835  I've also deleted electronic mail addresses from the files as an
4836  anti-spam measure.
4837
4838
4839Release 2005j - 2005-06-13 14:34:13 -0400
4840
4841  These reflect changes to limit the length of time zone abbreviations
4842  and the characters used in those abbreviations.
4843
4844  There are also changes to handle POSIX-style "quoted" timezone
4845  environment variables.
4846
4847  The changes were circulated on the time zone mailing list; the only
4848  change since then was the removal of a couple of minimum-length of
4849  abbreviation checks.
4850
4851
4852Release data2005i - 2005-04-21 15:04:16 -0400
4853
4854  changes (most importantly to Nicaragua and Haiti) by Paul Eggert
4855
4856
4857Release 2005h - 2005-04-04 11:24:47 -0400
4858
4859  changes by Paul Eggert
4860
4861  minor changes to Makefile and zdump.c to produce more useful output
4862  when doing a "make typecheck"
4863
4864
4865Release 2005g - 2005-03-14 10:11:21 -0500
4866
4867  changes by Paul Eggert (a change to current DST rules in Uruguay and
4868  an update to a link to time zone software)
4869
4870
4871Release 2005f - 2005-03-01 08:45:32 -0500
4872
4873  data and documentation changes by Paul Eggert
4874
4875
4876Release 2005e - 2005-02-10 15:59:44 -0500
4877
4878  [not summarized]
4879
4880
4881Release code2005d - 2005-01-31 09:21:47 -0500
4882
4883  make zic complain about links to links if the -v flag is used
4884
4885  have "make public" do more code checking
4886
4887  add an include to "localtime.c" for the benefit of gcc systems
4888
4889
4890Release 2005c - 2005-01-17 18:36:29 -0500
4891
4892  get better results when mktime runs on a system where time_t is double
4893
4894  changes to the data files (most importantly to Paraguay)
4895
4896
4897Release 2005b - 2005-01-10 09:19:54 -0500
4898
4899  Get localtime and gmtime working on systems with exotic time_t types.
4900
4901  Update the leap second commentary in the "leapseconds" file.
4902
4903
4904Release 2005a - 2005-01-01 13:13:44 -0500
4905
4906  [not summarized]
4907
4908
4909Release code2004i - 2004-12-14 13:42:58 -0500
4910
4911  Deal with systems where time_t is unsigned.
4912
4913
4914Release code2004h - 2004-12-07 11:40:18 -0500
4915
4916  64-bit-time_t changes
4917
4918
4919Release 2004g - 2004-11-02 09:06:01 -0500
4920
4921  update to Cuba (taking effect this weekend)
4922
4923  other changes by Paul Eggert
4924
4925  correction of the spelling of Oslo
4926
4927  changed versions of difftime.c and private.h
4928
4929
4930Release code2004f - 2004-10-21 10:25:22 -0400
4931
4932  Cope with wide-ranging tm_year values.
4933
4934
4935Release 2004e - 2004-10-11 14:47:21 -0400
4936
4937  Brazil/Argentina/Israel changes by Paul Eggert
4938
4939  changes to tz-link.htm by Paul
4940
4941  one small fix to Makefile
4942
4943
4944Release 2004d - 2004-09-22 08:27:29 -0400
4945
4946  Avoid overflow problems when TM_YEAR_BASE is added to an integer.
4947
4948
4949Release 2004c - 2004-08-11 12:06:26 -0400
4950
4951  asctime-related changes
4952
4953  (variants of) some of the documentation changes suggested by Paul Eggert
4954
4955
4956Release 2004b - 2004-07-19 14:33:35 -0400
4957
4958  data changes by Paul Eggert - most importantly, updates for Argentina
4959
4960
4961Release 2004a - 2004-05-27 12:00:47 -0400
4962
4963  changes by Paul Eggert
4964
4965  Handle DST transitions that occur at the end of a month in some
4966  years but at the start of the following month in other years.
4967
4968  Add a copy of the correspondence that's the basis for claims about
4969  DST in the Navajo Nation.
4970
4971
4972Release 2003e - 2003-12-15 09:36:47 -0500
4973
4974  changes by Arthur David Olson (primarily code changes)
4975
4976  changes by Paul Eggert (primarily data changes)
4977
4978  minor changes to "Makefile" and "northamerica" (in the latter case,
4979  optimization of the "Toronto" rules)
4980
4981
4982Release 2003d - 2003-10-06 09:34:44 -0400
4983
4984  changes by Paul Eggert
4985
4986
4987Release 2003c - 2003-09-16 10:47:05 -0400
4988
4989  Fix bad returns in zic.c's inleap function.
4990  Thanks to Bradley White for catching the problem!
4991
4992
4993Release 2003b - 2003-09-16 07:13:44 -0400
4994
4995  Add a "--version" option (and documentation) to the zic and zdump commands.
4996
4997  changes to overflow/underflow checking in zic
4998
4999  a localtime typo fix.
5000
5001  Update the leapseconds and tz-art.htm files.
5002
5003
5004Release 2003a - 2003-03-24 09:30:54 -0500
5005
5006  changes by Paul Eggert
5007
5008  a few additions and modifications to the tz-art.htm file
5009
5010
5011Release 2002d - 2002-10-15 13:12:42 -0400
5012
5013  changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
5014
5015  There's also a new time zone quote in "tz-art.htm".
5016
5017
5018Release 2002c - 2002-04-04 11:55:20 -0500
5019
5020  changes by Paul Eggert
5021
5022  Change zic.c to avoid creating symlinks to files that don't exist.
5023
5024
5025Release 2002b - 2002-01-28 12:56:03 -0500
5026
5027  [These change notes are for Release 2002a, which was corrupted.
5028  2002b was a corrected version of 2002a.]
5029
5030  changes by Paul Eggert
5031
5032  Update the "leapseconds" file to note that there'll be no leap
5033  second at the end of June, 2002.
5034
5035  Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
5036
5037  Change to "difftime.c" to avoid sizeof problems.
5038
5039
5040Release 2001d - 2001-10-09 13:31:32 -0400
5041
5042  changes by Paul Eggert
5043
5044
5045Release 2001c - 2001-06-05 13:59:55 -0400
5046
5047  changes by Paul Eggert and Andrew Brown
5048
5049
5050Release 2001b - 2001-04-05 16:44:38 -0400
5051
5052  changes by Paul Eggert (modulo jnorgard's typo fix)
5053
5054  tz-art.htm has been HTMLified.
5055
5056
5057Release 2001a - 2001-03-13 12:57:44 -0500
5058
5059  changes by Paul Eggert
5060
5061  An addition to the "leapseconds" file: comments with the text of the
5062  latest IERS leap second notice.
5063
5064  Trailing white space has been removed from data file lines, and
5065  repeated spaces in "Rule Jordan" lines in the "asia" file have been
5066  converted to tabs.
5067
5068
5069Release 2000h - 2000-12-14 15:33:38 -0500
5070
5071  changes by Paul Eggert
5072
5073  one typo fix in the "art" file
5074
5075  With providence, this is the last update of the millennium.
5076
5077
5078Release 2000g - 2000-10-10 11:35:22 -0400
5079
5080  changes by Paul Eggert
5081
5082  correction of John Mackin's name submitted by Robert Elz
5083
5084  Garry Shandling's Daylight Saving Time joke (!?!) from the recent
5085  Emmy Awards broadcast.
5086
5087
5088Release 2000f - 2000-08-10 09:31:58 -0400
5089
5090  changes by Paul Eggert
5091
5092  Added information in "tz-art.htm" on a Seinfeld reference to DST.
5093
5094  Error checking and messages in the "yearistype" script have been
5095  improved.
5096
5097
5098Release 2000e - 2000-07-31 09:27:54 -0400
5099
5100  data changes by Paul Eggert
5101
5102  a change to the default value of the defined constant HAVE_STRERROR
5103
5104  the addition of a Dave Barry quote on DST to the tz-arts file
5105
5106
5107Release 2000d - 2000-04-20 15:43:04 -0400
5108
5109  changes to the documentation and code of strftime for C99 conformance
5110
5111  a bug fix for date.c
5112
5113  These are based on (though modified from) changes by Paul Eggert.
5114
5115
5116Release 2000c - 2000-03-04 10:31:43 -0500
5117
5118  changes by Paul Eggert
5119
5120
5121Release 2000b - 2000-02-21 12:16:29 -0500
5122
5123  changes by Paul Eggert and Joseph Myers
5124
5125  modest tweaks to the tz-art.htm and tz-link.htm files
5126
5127
5128Release 2000a - 2000-01-18 09:21:26 -0500
5129
5130  changes by Paul Eggert
5131
5132  The two hypertext documents have also been renamed.
5133
5134
5135Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
5136
5137  Paul Eggert's changes
5138
5139  additions to the "zic" manual page and the "Arts.htm" file
5140
5141
5142Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
5143
5144  [not summarized]
5145
5146
5147Release data1999h - 1999-10-07 03:50:29 -0400
5148
5149  changes by Paul Eggert to "europe" (most importantly, fixing
5150  Lithuania and Estonia)
5151
5152
5153Release 1999g - 1999-09-28 11:06:18 -0400
5154
5155  data changes by Paul Eggert (most importantly, the change for
5156  Lebanon that buys correctness for this coming Sunday)
5157
5158  The "code" file contains changes to "Makefile" and "checktab.awk" to
5159  allow better checking of time zone files before they are published.
5160
5161
5162Release 1999f - 1999-09-23 09:48:14 -0400
5163
5164  changes by Arthur David Olson and Paul Eggert
5165
5166
5167Release 1999e - 1999-08-17 15:20:54 -0400
5168
5169  changes circulated by Paul Eggert, although the change to handling
5170  of DST-specifying timezone names has been commented out for now
5171  (search for "XXX" in "localtime.c" for details).  These files also
5172  do not make any changes to the start of DST in Brazil.
5173
5174  In addition to Paul's changes, there are updates to "Arts.htm" and
5175  cleanups of URLs.
5176
5177
5178Release 1999d - 1999-03-30 11:31:07 -0500
5179
5180  changes by Paul Eggert
5181
5182  The Makefile's "make public" rule has also been changed to do a test
5183  compile of each individual time zone data file (which should help
5184  avoid problems such as the one we had with Nicosia).
5185
5186
5187Release 1999c - 1999-03-25 09:47:47 -0500
5188
5189  changes by Paul Eggert, most importantly the change for Chile.
5190
5191
5192Release 1999b - 1999-02-01 17:51:44 -0500
5193
5194  changes by Paul Eggert
5195
5196  code changes (suggested by Mani Varadarajan, mani at be.com) for
5197  correct handling of symbolic links when building using a relative directory
5198
5199  code changes to generate correct messages for failed links
5200
5201  updates to the URLs in Arts.htm
5202
5203
5204Release 1999a - 1999-01-19 16:20:29 -0500
5205
5206  error message internationalizations and corrections in zic.c and
5207  zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
5208  to whom thanks!)
5209
5210
5211Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
5212
5213  changes for Brazil, Chile, and Germany
5214
5215  support for use of "24:00" in the input files for the time zone compiler
5216
5217
5218Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
5219
5220  changes by Paul Eggert
5221
5222  correction to a define in the "private.h" file
5223
5224
5225Release data1998g - 1998-08-11 03:28:35 -0000
5226  [tzdata1998g.tar.gz is missing!]
5227
5228  Lithuanian change provided by mgedmin at pub.osf.it
5229
5230  Move creation of the GMT link with Etc/GMT to "etcetera" (from
5231  "backward") to ensure that the GMT file is created even where folks
5232  don't want the "backward" links (as suggested by Paul Eggert).
5233
5234
5235Release data1998f - 1998-07-20 13:50:00 -0000
5236  [tzdata1998f.tar.gz is missing!]
5237
5238  Update the "leapseconds" file to include the newly-announced
5239  insertion at the end of 1998.
5240
5241
5242Release code1998f - 1998-06-01 10:18:31 -0400
5243
5244  addition to localtime.c by Guy Harris
5245
5246
5247Release 1998e - 1998-05-28 09:56:26 -0400
5248
5249  The Makefile is changed to produce zoneinfo-posix rather than
5250  zoneinfo/posix, and to produce zoneinfo-leaps rather than
5251  zoneinfo/right.
5252
5253  data changes by Paul Eggert
5254
5255  changes from Guy Harris to provide asctime_r and ctime_r
5256
5257  A usno1998 file (substantially identical to usno1997) has been added.
5258
5259
5260Release 1998d - 1998-05-14 11:58:34 -0400
5261
5262  changes to comments (in particular, elimination of references to CIA maps).
5263  "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
5264  where changes occur.
5265
5266
5267Release 1998c - 1998-02-28 12:32:26 -0500
5268
5269  changes by Paul Eggert (save the "French correction," on which I'll
5270  wait for the dust to settle)
5271
5272  symlink changes
5273
5274  changes and additions to Arts.htm
5275
5276
5277Release 1998b - 1998-01-17 14:31:51 -0500
5278
5279  URL cleanups and additions
5280
5281
5282Release 1998a - 1998-01-13 12:37:35 -0500
5283
5284  changes by Paul Eggert
5285
5286
5287Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
5288
5289  changes by Paul Eggert, with minor modifications from Arthur David
5290  Olson to make the files more browser friendly
5291
5292
5293Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
5294
5295  minor changes to put "TZif" at the start of each timezone information file
5296
5297  a rule has also been added to the Makefile so you can
5298	make zones
5299  to just recompile the zone information files (rather than doing a
5300  full "make install" with its other effects).
5301
5302
5303Release data1997i - 1997-10-07 08:45:38 -0400
5304
5305  changes to Africa by Paul Eggert
5306
5307
5308Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
5309
5310  corrections for Uruguay (and other locations)
5311
5312  Arthur David Olson's simple-minded fix allowing mktime to both
5313  correctly handle leap seconds and correctly handle tm_sec values
5314  upon which arithmetic has been performed.
5315
5316
5317Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
5318
5319  Paul Eggert's updates
5320
5321  a small change to a function prototype;
5322
5323  "Music" has been renamed "Arts.htm", HTMLified, and augmented to
5324  include information on Around the World in Eighty Days.
5325
5326
5327Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
5328
5329  fixes to zic's error handling
5330
5331  changes inspired by the item circulated on Slovenia
5332
5333  The description of Web resources has been HTMLified for browsing
5334  convenience.
5335
5336  A new piece of tz-related music has been added to the "Music" file.
5337
5338
5339Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
5340
5341  Paul Eggert's latest suggestions
5342
5343
5344Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
5345
5346  changes to "zic.c" to correct performance of the "-s" option
5347
5348  a new file "usno1997"
5349
5350
5351Release data1997c - 1997-03-04 09:58:18 -0500
5352
5353  changes in Israel
5354
5355
5356Release 1997b - 1997-02-27 18:34:19 -0500
5357
5358  The data file incorporates the 1997 leap second.
5359
5360  The code file incorporates Arthur David Olson's take on the
5361  zic/multiprocessor/directory-creation situation.
5362
5363
5364Release 1997a - 1997-01-21 09:11:10 -0500
5365
5366  Paul Eggert's Antarctica (and other changes)
5367
5368  Arthur David Olson finessed the "getopt" issue by checking against
5369  both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
5370  is returned while SunOS 5.5's manual says EOF is returned).
5371
5372
5373Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
5374
5375  Paul Eggert's latest changes
5376
5377
5378Release code1996n - 1996-12-16 09:42:02 -0500
5379
5380  link snapping fix from Bruce Evans (via Garrett Wollman)
5381
5382
5383Release data1996m - 1996-11-24 02:37:34 -0000
5384  [tzdata1996m.tar.gz is missing!]
5385
5386  Paul Eggert's batch of changes
5387
5388
5389Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
5390
5391  No functional changes here; the files have simply been changed to
5392  make more use of ISO style dates in comments. The names of the above
5393  files now include the year in full.
5394
5395
5396Release code96l - 1996-09-08 17:12:20 -0400
5397
5398  tzcode96k was missing a couple of pieces.
5399
5400
5401Release 96k - 1996-09-08 16:06:22 -0400
5402
5403  the latest round of changes from Paul Eggert
5404
5405  the recent Year 2000 material
5406
5407
5408Release code96j - 1996-07-30 13:18:53 -0400
5409
5410  Set sp->typecnt as suggested by Timothy Patrick Murphy.
5411
5412
5413Release code96i - 1996-07-27 20:11:35 -0400
5414
5415  Paul's suggested patch for strftime %V week numbers
5416
5417
5418Release data96i - 1996-07-01 18:13:04 -0400
5419
5420  "northamerica" and "europe" changes by Paul Eggert
5421
5422
5423Release code96h - 1996-06-05 08:02:21 -0400
5424
5425  fix for handling transitions specified in Universal Time
5426
5427  Some "public domain" notices have also been added.
5428
5429
5430Release code96g - 1996-05-16 14:00:26 -0400
5431
5432  fix for the simultaneous-DST-and-zone-change challenge
5433
5434
5435Release data96h - 1996-05-09 17:40:51 -0400
5436
5437  changes by Paul Eggert
5438
5439
5440Release code96f-data96g - 1996-05-03 03:09:59 -0000
5441  [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
5442
5443  The changes get us some of the way to fixing the problems noted in Paul
5444  Eggert's letter yesterday (in addition to a few others).  The approach
5445  has been to make zic a bit smarter about figuring out what time zone
5446  abbreviations apply just after the time specified in the "UNTIL" part
5447  of a zone line.  Putting the smarts in zic means avoiding having
5448  transition times show up in both "Zone" lines and "Rule" lines, which
5449  in turn avoids multiple transition time entries in time zone files.
5450  (This also makes the zic input files such as "europe" a bit shorter and
5451  should ease maintenance.)
5452
5453
5454Release data96f - 1996-04-19 19:20:03 -0000
5455  [tzdata96f.tar.gz is missing!]
5456
5457  The only changes are to the "northamerica" file; the time zone
5458  abbreviation for Denver is corrected to MST (and MDT), and the
5459  comments for Mexico have been updated.
5460
5461
5462Release data96e - 1996-03-19 17:37:26 -0500
5463
5464  Proposals by Paul Eggert, in particular the Portugal change that
5465  comes into play at the end of this month.
5466
5467
5468Release data96d - 1996-03-18 20:49:39 -0500
5469
5470  [not summarized]
5471
5472
5473Release code96e - 1996-02-29 15:43:27 -0000
5474  [tzcode96e.tar.gz is missing!]
5475
5476  internationalization changes and the fix to the documentation for strftime
5477
5478
5479Release code96d-data96c - 1996-02-12 11:05:27 -0500
5480
5481  The "code" file simply updates Bob Kridle's electronic address.
5482
5483  The "data" file updates rules for Mexico.
5484
5485
5486Release data96b - 1996-01-27 15:44:42 -0500
5487
5488  Kiribati change
5489
5490
5491Release code96c - 1996-01-16 16:58:15 -0500
5492
5493  leap-year streamlining and binary-search changes
5494
5495  fix to newctime.3
5496
5497
5498Release code96b - 1996-01-10 20:42:39 -0500
5499
5500  fixes and enhancements from Paul Eggert, including code that
5501  emulates the behavior of recent versions of the SunOS "date"
5502  command.
5503
5504
5505Release 96a - 1996-01-06 09:08:24 -0500
5506
5507  Israel updates
5508
5509  fixes to strftime.c for correct ISO 8601 week number generation,
5510  plus support for two new formats ('G' and 'g') to give ISO 8601 year
5511  numbers (which are not necessarily the same as calendar year numbers)
5512
5513
5514Release code95i-data95m - 1995-12-21 12:46:47 -0500
5515
5516  The latest revisions from Paul Eggert are included, the usno1995
5517  file has been updated, and a new file ("WWW") covering useful URLs
5518  has been added.
5519
5520
5521Release code95h-data95l - 1995-12-19 18:10:12 -0500
5522
5523  A simplification of a macro definition, a change to data for Sudan,
5524  and (for last minute shoppers) notes in the "Music" file on the CD
5525  "Old Man Time".
5526
5527
5528Release code95g-data95k - 1995-10-30 10:32:47 -0500
5529
5530  (slightly reformatted) 8-bit-clean proposed patch
5531
5532  minor patch: US/Eastern -> America/New_York
5533
5534  snapshot of the USNO's latest data ("usno1995")
5535
5536  some other minor cleanups
5537
5538
5539Release code95f-data95j - 1995-10-28 21:01:34 -0000
5540  [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
5541
5542  European cleanups
5543
5544  support for 64-bit time_t's
5545
5546  optimization in localtime.c
5547
5548
5549Release code95e - 1995-10-13 13:23:57 -0400
5550
5551  the mktime change to scan from future to past when trying to find time zone
5552  offsets
5553
5554
5555Release data95i - 1995-09-26 10:43:26 -0400
5556
5557  For Canada/Central, guess that the Sun customer's "one week too
5558  early" was just a approximation, and the true error is one month
5559  too early.  This is consistent with the rest of Canada.
5560
5561
5562Release data95h - 1995-09-21 11:26:48 -0400
5563
5564  latest changes from Paul Eggert
5565
5566
5567Release code95d - 1995-09-14 11:14:45 -0400
5568
5569  the addition of a "Music" file, which documents four recorded
5570  versions of the tune "Save That Time".
5571
5572
5573Release data95g - 1995-09-01 17:21:36 -0400
5574
5575  "yearistype" correction
5576
5577
5578Release data95f - 1995-08-28 20:46:56 -0400
5579
5580  Paul Eggert's change to the australasia file
5581
5582
5583Release data95e - 1995-07-08 18:02:34 -0400
5584
5585  The only change is a leap second at the end of this year.
5586  Thanks to Bradley White for forwarding news on the leap second.
5587
5588
5589Release data95d - 1995-07-03 13:26:22 -0400
5590
5591  Paul Eggert's changes
5592
5593
5594Release data95c - 1995-07-02 19:19:28 -0400
5595
5596  changes to "asia", "backward", "europe", and "southamerica"
5597  (read: northamericacentrics need not apply)
5598
5599
5600Release code95c - 1995-03-13 14:00:46 -0500
5601
5602  one-line fix for sign extension problems in detzcode
5603
5604
5605Release 95b - 1995-03-04 11:22:38 -0500
5606
5607  Minor changes in both:
5608
5609  The "code" file contains a workaround for the lack of "unistd.h" in
5610  Microsoft C++ version 7.
5611
5612  The "data" file contains a fixed "Link" for America/Shiprock.
5613
5614
5615Release 94h - 1994-12-10 12:51:14 -0500
5616
5617  The files:
5618
5619  *	incorporate the changes to "zdump" and "date" to make changes to
5620	the "TZ" environment variable permanent;
5621
5622  *	incorporate the table changes by Paul Eggert;
5623
5624  *	include (and document) support for universal time specifications in
5625	data files - but do not (yet) include use of this feature in the
5626	data files.
5627
5628  Think of this as "TZ Classic" - the software has been set up not to break if
5629  universal time shows up in its input, and data entries have been
5630  left as is so as not to break existing implementations.
5631
5632
5633Release data94f - 1994-08-20 12:56:09 -0400
5634
5635  (with thanks!) the latest data updates from Paul Eggert
5636
5637
5638Release data94e - 1994-06-04 13:13:53 -0400
5639
5640  [not summarized]
5641
5642
5643Release code94g - 1994-05-05 12:14:07 -0400
5644
5645  fix missing "optind.c" and a reference to it in the Makefile
5646
5647
5648Release code94f - 1994-05-05 13:00:33 -0000
5649  [tzcode94f.tar.gz is missing!]
5650
5651  changes to avoid overflow in difftime, as well as changes to cope
5652  with the 52/53 challenge in strftime
5653
5654
5655Release code94e - 1994-03-30 23:32:59 -0500
5656
5657  change for the benefit of PCTS
5658
5659
5660Release 94d - 1994-02-24 15:42:25 -0500
5661
5662  Avoid clashes with POSIX semantics for zones such as GMT+4.
5663
5664  Some other very minor housekeeping is also present.
5665
5666
5667Release code94c - 1994-02-10 08:52:40 -0500
5668
5669  Fix bug where mkdirs was broken unless you compile with
5670  -fwritable-strings (which is generally losing to do).
5671
5672
5673Release 94b - 1994-02-07 10:04:33 -0500
5674
5675  work by Paul Eggert who notes:
5676
5677  I found another book of time zone histories by E W Whitman; it's not
5678  as extensive as Shanks but has a few goodies of its own.  I used it
5679  to update the tables.  I also fixed some more as a result of
5680  correspondence with Adam David and Peter Ilieve, and move some stray
5681  links from 'europe' to 'backward'.  I corrected some scanning errors
5682  in usno1989.
5683
5684  As far as the code goes, I fixed zic to allow years in the range
5685  INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
5686  And I cleaned up the zic documentation a little bit.
5687
5688
5689Release data94a - 1994-02-03 08:58:54 -0500
5690
5691  It simply incorporates the recently announced leap second into the
5692  "leapseconds" file.
5693
5694
5695Release 93g - 1993-11-22 17:28:27 -0500
5696
5697  Paul Eggert has provided a good deal of historic information (based
5698  on Shanks), and there are some code changes to deal with the buglets
5699  that crawled out in dealing with the new information.
5700
5701
5702Release 93f - 1993-10-15 12:27:46 -0400
5703
5704  Paul Eggert's changes
5705
5706
5707Release 93e - 1993-09-05 21:21:44 -0400
5708
5709  This has updated data for Israel, England, and Kwajalein.  There's
5710  also an update to "zdump" to cope with Kwajalein's 24-hour jump.
5711  Thanks to Paul Eggert and Peter Ilieve for the changes.
5712
5713
5714Release 93d - 1993-06-17 23:34:17 -0400
5715
5716  new fix and new data on Israel
5717
5718
5719Release 93c - 1993-06-06 19:31:55 -0400
5720
5721  [not summarized]
5722
5723
5724Release 93b - 1993-02-02 14:53:58 -0500
5725
5726  updated "leapseconds" file
5727
5728
5729Release 93 - 1993-01-08 07:01:06 -0500
5730
5731  At kre's suggestion, the package has been split in two - a code piece
5732  (which also includes documentation) that's only of use to folks who
5733  want to recompile things and a data piece useful to anyone who can
5734  run "zic".
5735
5736  The new version has a few changes to the data files, a few
5737  portability changes, and an off-by-one fix (with thanks to
5738  Tom Karzes at deshaw.com for providing a description and a
5739  solution).
5740
5741
5742Release 92c - 1992-11-21 17:35:36 -0000
5743  [tz92c.tar.Z is missing!]
5744
5745  The fallout from the latest round of DST transitions.
5746
5747  There are changes for Portugal, Saskatchewan, and "Pacific-New";
5748  there's also a change to "zic.c" that makes it portable to more systems.
5749
5750
5751Release 92 - 1992-04-25 18:17:03 -0000
5752  [tz92.tar.Z is missing!]
5753
5754  By popular demand (well, at any rate, following a request by kre at munnari)
5755
5756
5757The 1989 update of the time zone package featured:
5758
5759  *	POSIXization (including interpretation of POSIX-style TZ environment
5760	variables, provided by Guy Harris),
5761  *	ANSIfication (including versions of "mktime" and "difftime"),
5762  *	SVIDulation (an "altzone" variable)
5763  *	MACHination (the "gtime" function)
5764  *	corrections to some time zone data (including corrections to the rules
5765	for Great Britain and New Zealand)
5766  *	reference data from the United States Naval Observatory for folks who
5767	want to do additional time zones
5768  *	and the 1989 data for Saudi Arabia.
5769
5770  (Since this code will be treated as "part of the implementation" in some
5771  places and as "part of the application" in others, there's no good way to
5772  name functions, such as timegm, that are not part of the proposed ANSI C
5773  standard; such functions have kept their old, underscore-free names in this
5774  update.)
5775
5776  And the "dysize" function has disappeared; it was present to allow
5777  compilation of the "date" command on old BSD systems, and a version of "date"
5778  is now provided in the package.  The "date" command is not created when you
5779  "make all" since it may lack options provided by the version distributed with
5780  your operating system, or may not interact with the system in the same way
5781  the native version does.
5782
5783  Since POSIX frowns on correct leap second handling, the default behavior of
5784  the "zic" command (in the absence of a "-L" option) has been changed to omit
5785  leap second information from its output files.
5786
5787
5788-----
5789Notes
5790
5791This file contains copies of the part of each release announcement
5792that talks about the changes in that release.  The text has been
5793adapted and reformatted for the purposes of this file.
5794
5795Traditionally a release R consists of a pair of tarball files,
5796tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
5797code2010a, data2012c) consist of just one or the other tarball, and a
5798few (e.g., code2012c-data2012d) have tarballs with mixed version
5799numbers.  Recent releases also come in an experimental format
5800consisting of a single tarball tzdb-R.tar.lz with extra data.
5801
5802Release timestamps are taken from the release's commit (for newer,
5803Git-based releases), from the newest file in the tarball (for older
5804releases, where this info is available) or from the email announcing
5805the release (if all else fails; these are marked with a time zone
5806abbreviation of -0000 and an "is missing!" comment).
5807
5808Earlier versions of the code and data were not announced on the tz
5809list and are not summarized here.
5810
5811This file is in the public domain.
5812
5813Local Variables:
5814coding: utf-8
5815End:
5816