xref: /freebsd/contrib/tzdata/NEWS (revision 38a52bd3b5cac3da6f7f6eef3dd050e6aa08ebb3)
1News for the tz database
2
3Release 2022e - 2022-10-11 11:13:02 -0700
4
5  Briefly:
6    Jordan and Syria switch from +02/+03 with DST to year-round +03.
7
8  Changes to future timestamps
9
10    Jordan and Syria are abandoning the DST regime and are changing to
11    permanent +03, so they will not fall back from +03 to +02 on
12    2022-10-28.  (Thanks to Steffen Thorsen and Issam Al-Zuwairi.)
13
14  Changes to past timestamps
15
16    On 1922-01-01 Tijuana adopted standard time at 00:00, not 01:00.
17
18  Changes to past time zone abbreviations and DST flags
19
20    The temporary advancement of clocks in central Mexico in summer
21    1931 is now treated as daylight saving time, instead of as two
22    changes to standard time.
23
24
25Release 2022d - 2022-09-23 12:02:57 -0700
26
27  Briefly:
28    Palestine transitions are now Saturdays at 02:00.
29    Simplify three Ukraine zones into one.
30
31  Changes to future timestamps
32
33    Palestine now springs forward and falls back at 02:00 on the
34    first Saturday on or after March 24 and October 24, respectively.
35    This means 2022 falls back 10-29 at 02:00, not 10-28 at 01:00.
36    (Thanks to Heba Hamad.)
37
38  Changes to past timestamps
39
40    Simplify three Ukraine zones to one, since the post-1970
41    differences seem to have been imaginary.  Move Europe/Uzhgorod and
42    Europe/Zaporozhye to 'backzone'; backward-compatibility links
43    still work, albeit with different timestamps before October 1991.
44
45
46Release 2022c - 2022-08-15 17:47:18 -0700
47
48  Briefly:
49    Work around awk bug in FreeBSD, macOS, etc.
50    Improve tzselect on intercontinental Zones.
51
52  Changes to code
53
54    Work around a bug in onetrueawk that broke commands like
55    'make traditional_tarballs' on FreeBSD, macOS, etc.
56    (Problem reported by Deborah Goldsmith.)
57
58    Add code to tzselect that uses experimental structured comments in
59    zone1970.tab to clarify whether Zones like Africa/Abidjan and
60    Europe/Istanbul cross continent or ocean boundaries.
61    (Inspired by a problem reported by Peter Krefting.)
62
63    Fix bug with 'zic -d /a/b/c' when /a is unwritable but the
64    directory /a/b already exists.
65
66    Remove zoneinfo2tdf.pl, as it was unused and triggered false
67    malware alarms on some email servers.
68
69
70Release 2022b - 2022-08-10 15:38:32 -0700
71
72  Briefly:
73    Chile's DST is delayed by a week in September 2022.
74    Iran no longer observes DST after 2022.
75    Rename Europe/Kiev to Europe/Kyiv.
76    New zic -R option
77    Vanguard form now uses %z.
78    Finish moving duplicate-since-1970 zones to 'backzone'.
79    New build option PACKRATLIST
80    New tailored_tarballs target, replacing rearguard_tarballs
81
82  Changes to future timestamps
83
84    Chile's 2022 DST start is delayed from September 4 to September 11.
85    (Thanks to Juan Correa.)
86
87    Iran plans to stop observing DST permanently, after it falls back
88    on 2022-09-21.  (Thanks to Ali Mirjamali.)
89
90  Changes to past timestamps
91
92    Finish moving to 'backzone' the location-based zones whose
93    timestamps since 1970 are duplicates; adjust links accordingly.
94    This change ordinarily affects only pre-1970 timestamps, and with
95    the new PACKRATLIST option it does not affect any timestamps.
96    In this round the affected zones are Antarctica/Vostok,
97    Asia/Brunei, Asia/Kuala_Lumpur, Atlantic/Reykjavik,
98    Europe/Amsterdam, Europe/Copenhagen, Europe/Luxembourg,
99    Europe/Monaco, Europe/Oslo, Europe/Stockholm, Indian/Christmas,
100    Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Reunion,
101    Pacific/Chuuk, Pacific/Funafuti, Pacific/Majuro, Pacific/Pohnpei,
102    Pacific/Wake and Pacific/Wallis, and the affected links are
103    Arctic/Longyearbyen, Atlantic/Jan_Mayen, Iceland, Pacific/Ponape,
104    Pacific/Truk, and Pacific/Yap.
105
106    From fall 1994 through fall 1995, Shanks wrote that Crimea's
107    DST transitions were at 02:00 standard time, not at 00:00.
108    (Thanks to Michael Deckers.)
109
110    Iran adopted standard time in 1935, not 1946.  In 1977 it observed
111    DST from 03-21 23:00 to 10-20 24:00; its 1978 transitions were on
112    03-24 and 08-05, not 03-20 and 10-20; and its spring 1979
113    transition was on 05-27, not 03-21.
114    (Thanks to Roozbeh Pournader and Francis Santoni.)
115
116    Chile's observance of -04 from 1946-08-29 through 1947-03-31 was
117    considered DST, not standard time.  Santiago and environs had moved
118    their clocks back to rejoin the rest of mainland Chile; put this
119    change at the end of 1946-08-28.  (Thanks to Michael Deckers.)
120
121    Some old, small clock transitions have been removed, as people at
122    the time did not change their clocks.  This affects Asia/Hong_Kong
123    in 1904, Asia/Ho_Chi_Minh in 1906, and Europe/Dublin in 1880.
124
125  Changes to zone name
126
127    Rename Europe/Kiev to Europe/Kyiv, as "Kyiv" is more common in
128    English now.  Spelling of other names in Ukraine has not yet
129    demonstrably changed in common English practice so for now these
130    names retain old spellings, as in other countries (e.g.,
131    Europe/Prague not "Praha", and Europe/Sofia not "Sofiya").
132
133  Changes to code
134
135    zic has a new option '-R @N' to output explicit transitions < N.
136    (Need suggested by Almaz Mingaleev.)
137
138    'zic -r @N' no longer outputs bad data when N < first transition.
139    (Problem introduced in 2021d and reported by Peter Krefting.)
140
141    zic now checks its input for NUL bytes and unterminated lines, and
142    now supports input line lengths up to 2048 (not 512) bytes.
143
144    gmtime and related code now use the abbreviation "UTC" not "GMT".
145    POSIX is being revised to require this.
146
147    When tzset and related functions set vestigial static variables
148    like tzname, they now prefer specified timestamps to unspecified ones.
149    (Problem reported by Almaz Mingaleev.)
150
151    zic no longer complains "can't determine time zone abbreviation to
152    use just after until time" when a transition to a new standard
153    time occurs simultaneously with the first DST fallback transition.
154
155  Changes to build procedure
156
157    Source data in vanguard form now uses the %z notation, introduced
158    in release 2015f.  For example, for America/Sao_Paulo vanguard
159    form contains the zone continuation line "-3:00 Brazil %z", which
160    is simpler and more reliable than the line "-3:00 Brazil -03/-02"
161    used in main and rearguard forms.  The plan is for the main form
162    to use %z eventually; in the meantime maintainers of zi parsers
163    are encouraged to test the parsers on vanguard.zi.
164
165    The Makefile has a new PACKRATLIST option to select a subset of
166    'backzone'.  For example, 'make PACKRATDATA=backzone
167    PACKRATLIST=zone.tab' now generates TZif files identical to those
168    of the global-tz project.
169
170    The Makefile has a new tailored_tarballs target for generating
171    special-purpose tarballs.  It generalizes and replaces the
172    rearguard_tarballs target and related targets and macros, which
173    are now obsolescent.
174
175    'make install' now defaults LOCALTIME to Factory not GMT,
176    which means the default abbreviation is now "-00" not "GMT".
177
178    Remove the posix_packrat target, marked obsolescent in 2016a.
179
180
181Release 2022a - 2022-03-15 23:02:01 -0700
182
183  Briefly:
184    Palestine will spring forward on 2022-03-27, not -03-26.
185    zdump -v now outputs better failure indications.
186    Bug fixes for code that reads corrupted TZif data.
187
188  Changes to future timestamps
189
190    Palestine will spring forward on 2022-03-27, not 2022-03-26.
191    (Thanks to Heba Hamad.)  Predict future transitions for first
192    Sunday >= March 25.  Additionally, predict fallbacks to be the first
193    Friday on or after October 23, not October's last Friday, to be more
194    consistent with recent practice.  The first differing fallback
195    prediction is on 2025-10-24, not 2025-10-31.
196
197  Changes to past timestamps
198
199    From 1992 through spring 1996, Ukraine's DST transitions were at
200    02:00 standard time, not at 01:00 UTC.  (Thanks to Alois Treindl.)
201
202    Chile's Santiago Mean Time and its LMT precursor have been adjusted
203    eastward by 1 second to align with past and present law.
204
205  Changes to commentary
206
207    Add several references for Chile's 1946/1947 transitions, some of
208    which only affected portions of the country.
209
210  Changes to code
211
212    Fix bug when mktime gets confused by truncated TZif files with
213    unspecified local time.  (Problem reported by Almaz Mingaleev.)
214
215    Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
216    (Problem reported by Christos Zoulas.)
217
218    When reading a version 2 or later TZif file, the TZif reader now
219    validates the version 1 header and data block only enough to skip
220    over them, as recommended by RFC 8536 section 4.  Also, the TZif
221    reader no longer mistakenly attempts to parse a version 1 TZIf
222    file header as a TZ string.
223
224    zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
225    when local time and UT cannot be determined for a timestamp.
226
227  Changes to build procedure
228
229    Distribution tarballs now use standard POSIX.1-1988 ustar format
230    instead of GNU format.  Although the formats are almost identical
231    for these tarballs, ustar headers' magic fields contain "ustar"
232    instead of "ustar ", and their version fields contain "00" instead
233    of " ".  The two formats are planned to diverge more significantly
234    for tzdb releases after 2242-03-16 12:56:31 UTC, when the ustar
235    format becomes obsolete and the tarballs switch to pax format, an
236    extension of ustar.  For details about these formats, please see
237    "pax - portable archive interchange", IEEE Std 1003.1-2017,
238    <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13>.
239
240
241Release 2021e - 2021-10-21 18:41:00 -0700
242
243  Changes to future timestamps
244
245    Palestine will fall back 10-29 (not 10-30) at 01:00.
246    (Thanks to P Chan and Heba Hemad.)
247
248
249Release 2021d - 2021-10-15 13:48:18 -0700
250
251  Briefly:
252    Fiji suspends DST for the 2021/2022 season.
253    'zic -r' marks unspecified timestamps with "-00".
254
255  Changes to future timestamps
256
257    Fiji will suspend observance of DST for the 2021/2022 season.
258    Assume for now that it will return next year.  (Thanks to Jashneel
259    Kumar and P Chan.)
260
261  Changes to code
262
263    'zic -r' now uses "-00" time zone abbreviations for intervals
264    with UT offsets that are unspecified due to -r truncation.
265    This implements a change in draft Internet RFC 8536bis.
266
267
268Release 2021c - 2021-10-01 14:21:49 -0700
269
270  Briefly:
271    Revert most 2021b changes to 'backward'.
272    Fix 'zic -b fat' bug in pre-1970 32-bit data.
273    Fix two Link line typos.
274    Distribute SECURITY file.
275
276    This release is intended as a bugfix release, to fix compatibility
277    problems and typos reported since 2021b was released.
278
279  Changes to Link directives
280
281    Revert almost all of 2021b's changes to the 'backward' file,
282    by moving Link directives back to where they were in 2021a.
283    Although 'zic' doesn't care which source file contains a Link
284    directive, some downstream uses ran into trouble with the move.
285    (Problem reported by Stephen Colebourne for Joda-Time.)
286
287    Fix typo that linked Atlantic/Jan_Mayen to the wrong location
288    (problem reported by Chris Walton).
289
290    Fix 'backzone' typo that linked America/Virgin to the wrong
291    location (problem reported by Michael Deckers).
292
293  Changes to code
294
295    Fix a bug in 'zic -b fat' that caused old timestamps to be
296    mishandled in 32-bit-only readers (problem reported by Daniel
297    Fischer).
298
299  Changes to documentation
300
301    Distribute the SECURITY file (problem reported by Andreas Radke).
302
303
304Release 2021b - 2021-09-24 16:23:00 -0700
305
306  Briefly:
307    Jordan now starts DST on February's last Thursday.
308    Samoa no longer observes DST.
309    Merge more location-based Zones whose timestamps agree since 1970.
310    Move some backward-compatibility links to 'backward'.
311    Rename Pacific/Enderbury to Pacific/Kanton.
312    Correct many pre-1993 transitions in Malawi, Portugal, etc.
313    zic now creates each output file or link atomically.
314    zic -L no longer omits the POSIX TZ string in its output.
315    zic fixes for truncation and leap second table expiration.
316    zic now follows POSIX for TZ strings using all-year DST.
317    Fix some localtime crashes and bugs in obscure cases.
318    zdump -v now outputs more-useful boundary cases.
319    tzfile.5 better matches a draft successor to RFC 8536.
320    A new file SECURITY.
321
322    This release is prompted by recent announcements by Jordan and Samoa.
323    It incorporates many other changes that had accumulated since 2021a.
324    However, it omits most proposed changes that merged all Zones
325    agreeing since 1970, as concerns were raised about doing too many of
326    these changes at once.  It does keeps some of these changes in the
327    interest of making tzdb more equitable one step at a time; see
328    "Merge more location-based Zones" below.
329
330  Changes to future timestamps
331
332    Jordan now starts DST on February's last Thursday.
333    (Thanks to Steffen Thorsen.)
334
335    Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
336
337  Changes to zone name
338
339    Rename Pacific/Enderbury to Pacific/Kanton.  When we added
340    Enderbury in 1993, we did not know that it is uninhabited and that
341    Kanton (population two dozen) is the only inhabited location in
342    that timezone.  The old name is now a backward-compatibility link.
343
344  Changes to past timestamps
345
346    Correct many pre-1993 transitions, fixing entries originally
347    derived from Shanks, Whitman, and Mundell.  The fixes include:
348      - Barbados: standard time was introduced in 1911, not 1932; and
349	DST was observed in 1942-1944
350      - Cook Islands: In 1899 they switched from east to west of GMT,
351	celebrating Christmas for two days.  They (and Niue) switched
352	to standard time in 1952, not 1901.
353      - Guyana: corrected LMT for Georgetown; the introduction of
354	standard time in 1911, not 1915; and corrections to 1975 and
355	1992 transitions
356      - Kanton: uninhabited before 1937-08-31
357      - Niue: only observed -11:20 from 1952 through 1964, then went to
358        -11 instead of -11:30
359      - Portugal: DST was observed in 1950
360      - Tonga: corrected LMT; the introduction of standard time in 1945,
361        not 1901; and corrections to the transition from +12:20 to +13
362        in 1961, not 1941
363    Additional fixes to entries in the 'backzone' file include:
364      - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
365      - The Gambia: 1933 and 1942 transitions
366      - Malawi: several 1911 through 1925 transitions
367      - Sierra Leone: several 1913 through 1941 transitions, and DST
368	was NOT observed in 1957 through 1962
369    (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
370    Alois Treindl.)
371
372    Merge more location-based Zones whose timestamps agree since 1970,
373    as pre-1970 timestamps are out of scope.  This is part of a
374    process that has been ongoing since 2013.  This does not affect
375    post-1970 timestamps, and timezone historians who build with 'make
376    PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
377    When merging, keep the most-populous location's data, and move
378    data for other locations to 'backzone' with a backward
379    link in 'backward'.  For example, move America/Creston data to
380    'backzone' with a link in 'backward' from America/Phoenix because
381    the two timezones' timestamps agree since 1970; this change
382    affects some pre-1968 timestamps in America/Creston because
383    Creston and Phoenix disagreed before 1968.  The affected Zones
384    are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
385    America/Creston, America/Curacao, America/Nassau,
386    America/Port_of_Spain, Antarctica/DumontDUrville, and
387    Antarctica/Syowa.
388
389  Changes to maintenance procedure
390
391    The new file SECURITY covers how to report security-related bugs.
392
393    Several backward-compatibility links have been moved to the
394    'backward' file.  These links, which range from Africa/Addis_Ababa
395    to Pacific/Saipan, are only for compatibility with now-obsolete
396    guidelines suggesting an entry for every ISO 3166 code.
397    The intercontinental convenience links Asia/Istanbul and
398    Europe/Nicosia have also been moved to 'backward'.
399
400  Changes to code
401
402    zic now creates each output file or link atomically,
403    possibly by creating a temporary file and then renaming it.
404    This avoids races where a TZ setting would temporarily stop
405    working while zic was installing a replacement file or link.
406
407    zic -L no longer omits the POSIX TZ string in its output.
408    Starting with 2020a, zic -L truncated its output according to the
409    "Expires" directive or "#expires" comment in the leapseconds file.
410    The resulting TZif files omitted daylight saving transitions after
411    the leap second table expired, which led to far less-accurate
412    predictions of times after the expiry.  Although future timestamps
413    cannot be converted accurately in the presence of leap seconds, it
414    is more accurate to convert near-future timestamps with a few
415    seconds error than with an hour error, so zic -L no longer
416    truncates output in this way.
417
418    Instead, when zic -L is given the "Expires" directive, it now
419    outputs the expiration by appending a no-change entry to the leap
420    second table.  Although this should work well with most TZif
421    readers, it does not conform to Internet RFC 8536 and some pickier
422    clients (including tzdb 2017c through 2021a) reject it, so
423    "Expires" directives are currently disabled by default.  To enable
424    them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
425    this new feature it is marked with a new TZif version number 4,
426    a format intended to be documented in a successor to RFC 8536.
427
428    zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
429    that omits leap second information for the range LO..B when LO
430    falls between two leap seconds A and B.  Instead, it generates a
431    TZif version 4 file that represents the previously-missing
432    information.
433
434    The TZif reader now allows the leap second table to begin with a
435    correction other than -1 or +1, and to contain adjacent
436    transitions with equal corrections.  This supports TZif version 4.
437
438    The TZif reader now lets leap seconds occur less than 28 days
439    apart.  This supports possible future TZif extensions.
440
441    Fix bug that caused 'localtime' etc. to crash when TZ was
442    set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
443    not conform to POSIX but does conform to Internet RFC 8536.
444
445    Fix another bug that caused 'localtime' etc. to crash when TZ was
446    set to a POSIX-conforming but unusual TZ string like
447    "EST5EDT4,0/0,J365/0", where almost all the year is DST.
448
449    Fix yet another bug that caused 'localtime' etc. to mishandle slim
450    TZif files containing leap seconds after the last explicit
451    transition in the table, or when handling far-future timestamps
452    in slim TZif files lacking leap seconds.
453
454    Fix localtime misbehavior involving positive leap seconds.
455    This change affects only behavior for "right" system time,
456    which contains leap seconds, and only if the UT offset is
457    not a multiple of 60 seconds when a positive leap second occurs.
458    (No such timezone exists in tzdb, luckily.)  Without the fix,
459    the timestamp was ambiguous during a positive leap second.
460    With the fix, any seconds occurring after a positive leap second
461    and within the same localtime minute are counted through 60, not
462    through 59; their UT offset (tm_gmtoff) is the same as before.
463    Here is how the fix affects timestamps in a timezone with UT
464    offset +01:23:45 (5025 seconds) and with a positive leap second at
465    1972-06-30 23:59:60 UTC (78796800):
466
467	time_t    without the fix      with the fix
468	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
469	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
470	...
471	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
472	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
473
474    Fix an unlikely bug that caused 'localtime' etc. to misbehave if
475    civil time changes a few seconds before time_t wraps around, when
476    leap seconds are enabled.
477
478    Fix bug in zic -r; in some cases, the dummy time type after the
479    last time transition disagreed with the TZ string, contrary to
480    Internet RFC 8563 section 3.3.
481
482    Fix a bug with 'zic -r @X' when X is a negative leap second that
483    has a nonnegative correction.  Without the fix, the output file
484    was truncated so that X appeared to be a positive leap second.
485    Fix a similar, even-less-likely bug when truncating at a positive
486    leap second that has a nonpositive correction.
487
488    zic -r now reports an error if given rolling leap seconds, as this
489    usage has never generally worked and is evidently unused.
490
491    zic now generates a POSIX-conforming TZ string for TZif files
492    where all-year DST is predicted for the indefinite future.
493    For example, for all-year Eastern Daylight Time, zic now generates
494    "XXX3EDT4,0/0,J365/23" where it previously generated
495    "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
496    noting the possibility of POSIX conformance.)
497
498    zic.c no longer requires sys/wait.h (thanks to spazmodius for
499    noting it wasn't needed).
500
501    When reading slim TZif files, zdump no longer mishandles leap
502    seconds on the rare platforms where time_t counts leap seconds,
503    fixing a bug introduced in 2014g.
504
505    zdump -v now outputs timestamps at boundaries of what localtime
506    and gmtime can represent, instead of the less-useful timestamps
507    one day after the minimum and one day before the maximum.
508    (Thanks to Arthur David Olson for prototype code, and to Manuela
509    Friedrich for debugging help.)
510
511    zdump's -c and -t options are now consistently inclusive for the
512    lower time bound and exclusive for the upper.  Formerly they were
513    inconsistent.  (Confusion noted by Martin Burnicki.)
514
515  Changes to build procedure
516
517    You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
518    non-POSIX hosts where malloc doesn't set errno.
519    (Problem reported by Jan Engelhardt.)
520
521  Changes to documentation
522
523    tzfile.5 better matches a draft successor to RFC 8536
524    <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.
525
526
527Release 2021a - 2021-01-24 10:54:57 -0800
528
529  Changes to future timestamps
530
531    South Sudan changes from +03 to +02 on 2021-02-01 at 00:00.
532    (Thanks to Steffen Thorsen.)
533
534
535Release 2020f - 2020-12-29 00:17:46 -0800
536
537  Change to build procedure
538
539    'make rearguard_tarballs' no longer generates a bad rearguard.zi,
540    fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
541
542
543Release 2020e - 2020-12-22 15:14:34 -0800
544
545  Briefly:
546    Volgograd switches to Moscow time on 2020-12-27 at 02:00.
547
548  Changes to future timestamps
549
550    Volgograd changes time zone from +04 to +03 on 2020-12-27 at 02:00.
551    (Thanks to Alexander Krivenyshev and Stepan Golosunov.)
552
553  Changes to past timestamps
554
555    Correct many pre-1986 transitions, fixing entries originally
556    derived from Shanks.  The fixes include:
557      - Australia: several 1917 through 1971 transitions
558      - The Bahamas: several 1941 through 1945 transitions
559      - Bermuda: several 1917 through 1956 transitions
560      - Belize: several 1942 through 1968 transitions
561      - Ghana: several 1915 through 1956 transitions
562      - Israel and Palestine: several 1940 through 1985 transitions
563      - Kenya and adjacent: several 1908 through 1960 transitions
564      - Nigeria and adjacent: correcting LMT in Lagos, and several 1905
565        through 1919 transitions
566      - Seychelles: the introduction of standard time in 1907, not 1906
567      - Vanuatu: DST in 1973-1974, and a corrected 1984 transition
568    (Thanks to P Chan.)
569
570    Because of the Australia change, Australia/Currie (King Island) is
571    no longer needed, as it is identical to Australia/Hobart for all
572    timestamps since 1970 and was therefore created by mistake.
573    Australia/Currie has been moved to the 'backward' file and its
574    corrected data moved to the 'backzone' file.
575
576  Changes to past time zone abbreviations and DST flags
577
578    To better match legislation in Turks and Caicos, the 2015 shift to
579    year-round observance of -04 is now modeled as AST throughout before
580    returning to Eastern Time with US DST in 2018, rather than as
581    maintaining EDT until 2015-11-01.  (Thanks to P Chan.)
582
583  Changes to documentation
584
585    The zic man page now documents zic's coalescing of transitions
586    when a zone falls back just before DST springs forward.
587
588
589Release 2020d - 2020-10-21 11:24:13 -0700
590
591  Briefly:
592    Palestine ends DST earlier than predicted, on 2020-10-24.
593
594  Changes to past and future timestamps
595
596    Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
597    as previously predicted (thanks to Sharef Mustafa.)  Its
598    2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
599    Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
600    its spring 2020 transition was on March 28 at 00:00, not March 27
601    (thanks to Pierre Cashon.)  This affects Asia/Gaza and
602    Asia/Hebron.  Assume future spring and fall transitions will be on
603    the Saturday preceding the last Sunday of March and October,
604    respectively.
605
606
607Release 2020c - 2020-10-16 11:15:53 -0700
608
609  Briefly:
610    Fiji starts DST later than usual, on 2020-12-20.
611
612  Changes to future timestamps
613
614    Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
615    previously predicted.  DST will still end on 2021-01-17.
616    (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
617    the later-than-usual start date is a one-time departure from the
618    recent pattern.
619
620  Changes to build procedure
621
622    Rearguard tarballs now contain an empty file pacificnew.
623    Some older downstream software expects this file to exist.
624    (Problem reported by Mike Cullinan.)
625
626
627Release 2020b - 2020-10-06 18:35:04 -0700
628
629  Briefly:
630    Revised predictions for Morocco's changes starting in 2023.
631    Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
632    Macquarie Island has stayed in sync with Tasmania since 2011.
633    Casey, Antarctica is at +08 in winter and +11 in summer.
634    zic no longer supports -y, nor the TYPE field of Rules.
635
636  Changes to future timestamps
637
638    Morocco's spring-forward after Ramadan is now predicted to occur
639    no sooner than two days after Ramadan, instead of one day.
640    (Thanks to Milamber.)  The first altered prediction is for 2023,
641    now predicted to spring-forward on April 30 instead of April 23.
642
643  Changes to past and future timestamps
644
645   Casey Station, Antarctica has been using +08 in winter and +11 in
646   summer since 2018.  The most recent transition from +08 to +11 was
647   2020-10-04 00:01.  Also, Macquarie Island has been staying in
648   sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
649
650  Changes to past and future time zone abbreviations and DST flags
651
652    Canada's Yukon, represented by America/Whitehorse and
653    America/Dawson, changes its time zone rules from -08/-07 to
654    permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
655    This change affects only the time zone abbreviation (MST vs PDT)
656    and daylight saving flag for the period between the two dates.
657    (Thanks to Andrew G. Smith.)
658
659  Changes to past timestamps
660
661    Correct several transitions for Hungary for 1918/1983.
662    For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
663    (Thanks to Géza Nyáry.)  Also, the 1890 transition to standard
664    time was on 11-01, not 10-01 (thanks to Michael Deckers).
665
666    The 1891 French transition was on March 16, not March 15.  The
667    1911-03-11 French transition was at midnight, not a minute later.
668    Monaco's transitions were on 1892-06-01 and 1911-03-29, not
669    1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
670
671  Changes to code
672
673    Support for zic's long-obsolete '-y YEARISTYPE' option has been
674    removed and, with it, so has support for the TYPE field in Rule
675    lines, which is now reserved for compatibility with earlier zic.
676    These features were previously deprecated in release 2015f.
677    (Thanks to Tim Parenti.)
678
679    zic now defaults to '-b slim' instead of to '-b fat'.
680
681    zic's new '-l -' and '-p -' options uninstall any existing
682    localtime and posixrules files, respectively.
683
684    The undocumented and ineffective tzsetwall function has been
685    removed.
686
687  Changes to build procedure
688
689    The Makefile now defaults POSIXRULES to '-', so the posixrules
690    feature (obsolete as of 2019b) is no longer installed by default.
691
692  Changes to documentation and commentary
693
694    The long-obsolete files pacificnew, systemv, and yearistype.sh have
695    been removed from the distribution.  (Thanks to Tim Parenti.)
696
697
698Release 2020a - 2020-04-23 16:03:47 -0700
699
700  Briefly:
701    Morocco springs forward on 2020-05-31, not 2020-05-24.
702    Canada's Yukon advanced to -07 year-round on 2020-03-08.
703    America/Nuuk renamed from America/Godthab.
704    zic now supports expiration dates for leap second lists.
705
706  Changes to future timestamps
707
708    Morocco's second spring-forward transition in 2020 will be May 31,
709    not May 24 as predicted earlier.  (Thanks to Semlali Naoufal.)
710    Adjust future-year predictions to use the first Sunday after the
711    day after Ramadan, not the first Sunday after Ramadan.
712
713    Canada's Yukon, represented by America/Whitehorse and
714    America/Dawson, advanced to -07 year-round, beginning with its
715    spring-forward transition on 2020-03-08, and will not fall back on
716    2020-11-01.  Although a government press release calls this
717    "permanent Pacific Daylight Saving Time", we prefer MST for
718    consistency with nearby Dawson Creek, Creston, and Fort Nelson.
719    (Thanks to Tim Parenti.)
720
721  Changes to past timestamps
722
723    Shanghai observed DST in 1919.  (Thanks to Phake Nick.)
724
725  Changes to timezone identifiers
726
727    To reflect current usage in English better, America/Godthab has
728    been renamed to America/Nuuk.  A backwards-compatibility link
729    remains for the old name.
730
731  Changes to code
732
733    localtime.c no longer mishandles timestamps after the last
734    transition in a TZif file with leap seconds and with daylight
735    saving time transitions projected into the indefinite future.
736    For example, with TZ='America/Los_Angeles' with leap seconds,
737    zdump formerly reported a DST transition on 2038-03-14
738    from 01:59:32.999... to 02:59:33 instead of the correct transition
739    from 01:59:59.999... to 03:00:00.
740
741    zic -L now supports an Expires line in the leapseconds file, and
742    truncates the TZif output accordingly.  This propagates leap
743    second expiration information into the TZif file, and avoids the
744    abovementioned localtime.c bug as well as similar bugs present in
745    many client implementations.  If no Expires line is present, zic
746    -L instead truncates the TZif output based on the #expires comment
747    present in leapseconds files distributed by tzdb 2018f and later;
748    however, this usage is obsolescent.  For now, the distributed
749    leapseconds file has an Expires line that is commented out, so
750    that the file can be fed to older versions of zic which ignore the
751    commented-out line.  Future tzdb distributions are planned to
752    contain a leapseconds file with an Expires line.
753
754    The configuration macros HAVE_TZNAME and USG_COMPAT should now be
755    set to 1 if the system library supports the feature, and 2 if not.
756    As before, these macros are nonzero if tzcode should support the
757    feature, zero otherwise.
758
759    The configuration macro ALTZONE now has the same values with the
760    same meaning as HAVE_TZNAME and USG_COMPAT.
761
762    The code's defense against CRLF in leap-seconds.list is now
763    portable to POSIX awk.  (Problem reported by Deborah Goldsmith.)
764
765    Although the undocumented tzsetwall function is not changed in
766    this release, it is now deprecated in preparation for removal in
767    future releases.  Due to POSIX requirements, tzsetwall has not
768    worked for some time.  Any code that uses it should instead use
769    tzalloc(NULL) or, if portability trumps thread-safety, should
770    unset the TZ environment variable.
771
772  Changes to commentary
773
774    The Îles-de-la-Madeleine and the Listuguj reserve are noted as
775    following America/Halifax, and comments about Yukon's "south" and
776    "north" have been corrected to say "east" and "west".  (Thanks to
777    Jeffery Nichols.)
778
779
780Release 2019c - 2019-09-11 08:59:48 -0700
781
782  Briefly:
783    Fiji observes DST from 2019-11-10 to 2020-01-12.
784    Norfolk Island starts observing Australian-style DST.
785
786  Changes to future timestamps
787
788    Fiji's next DST transitions will be 2019-11-10 and 2020-01-12
789    instead of 2019-11-03 and 2020-01-19.  (Thanks to Raymond Kumar.)
790    Adjust future guesses accordingly.
791
792    Norfolk Island will observe Australian-style DST starting in
793    spring 2019.  The first transition is on 2019-10-06.  (Thanks to
794    Kyle Czech and Michael Deckers.)
795
796  Changes to past timestamps
797
798    Many corrections to time in Turkey from 1940 through 1985.
799    (Thanks to Oya Vulaş via Alois Treindl, and to Kıvanç Yazan.)
800
801    The Norfolk Island 1975-03-02 transition was at 02:00 standard
802    time, not 02:00 DST.  (Thanks to Michael Deckers.)
803
804    South Korea observed DST from 1948 through 1951.  Although this
805    info was supposed to appear in release 2014j, a typo inadvertently
806    suppressed the change.  (Thanks to Alois Treindl.)
807
808    Detroit observed DST in 1967 and 1968 following the US DST rules,
809    except that its 1967 DST began on June 14 at 00:01.  (Thanks to
810    Alois Treindl for pointing out that the old data entries were
811    probably wrong.)
812
813    Fix several errors in pre-1970 transitions in Perry County, IN.
814    (Thanks to Alois Treindl for pointing out the 1967/9 errors.)
815
816    Edmonton did not observe DST in 1967 or 1969.  In 1946 Vancouver
817    ended DST on 09-29 not 10-13, and Vienna ended DST on 10-07 not
818    10-06.  In 1945 Königsberg (now Kaliningrad) switched from +01/+02
819    to +02/+03 on 04-10 not 01-01, and its +02/+03 is abbreviated
820    EET/EEST, not CET/CEST.  (Thanks to Alois Treindl.)  In 1946
821    Königsberg switched to +03 on 04-07 not 01-01.
822
823    In 1946 Louisville switched from CST to CDT on 04-28 at 00:01, not
824    01-01 at 00:00.  (Thanks to Alois Treindl and Michael Deckers.)
825    Also, it switched from CST to CDT on 1950-04-30, not 1947-04-27.
826
827    The 1892-05-01 transition in Brussels was at 00:17:30, not at noon.
828    (Thanks to Michael Deckers.)
829
830  Changes to past time zone abbreviations and DST flags
831
832    Hong Kong Winter Time, observed from 1941-10-01 to 1941-12-25,
833    is now flagged as DST and is abbreviated HKWT not HKT.
834
835  Changes to code
836
837    leapseconds.awk now relies only on its input data, rather than
838    also relying on its comments.  (Inspired by code from Dennis
839    Ferguson and Chris Woodbury.)
840
841    The code now defends against CRLFs in leap-seconds.list.
842    (Thanks to Brian Inglis and Chris Woodbury.)
843
844  Changes to documentation and commentary
845
846    theory.html discusses leap seconds.  (Thanks to Steve Summit.)
847
848    Nashville's newspapers dueled about the time of day in the 1950s.
849    (Thanks to John Seigenthaler.)
850
851    Liechtenstein observed Swiss DST in 1941/2.
852    (Thanks to Alois Treindl.)
853
854
855Release 2019b - 2019-07-01 00:09:53 -0700
856
857  Briefly:
858    Brazil no longer observes DST.
859    'zic -b slim' outputs smaller TZif files; please try it out.
860    Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
861
862  Changes to future timestamps
863
864    Brazil has canceled DST and will stay on standard time indefinitely.
865    (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
866    Oliveira.)
867
868    Predictions for Morocco now go through 2087 instead of 2037, to
869    work around a problem on newlib when using TZif files output by
870    zic 2019a or earlier.  (Problem reported by David Gauchard.)
871
872  Changes to past and future timestamps
873
874    Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
875    at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
876    future transitions to be March's last Friday at 00:00.
877
878  Changes to past timestamps
879
880    Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
881    03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
882    not 09-15 at 00:00.  In 1946 its spring-forward transition was on
883    04-21 at 00:00, not the previous day at 03:30.  From 1946 through
884    1952 its fall-back transitions occurred at 04:30, not at 03:30.
885    In 1947 its fall-back transition was on 11-30, not 12-30.
886    (Thanks to P Chan.)
887
888  Changes to past time zone abbreviations
889
890    Italy's 1866 transition to Rome Mean Time was on December 12, not
891    September 22.  This affects only the time zone abbreviation for
892    Europe/Rome between those dates.  (Thanks to Stephen Trainor and
893    Luigi Rosa.)
894
895  Changes affecting metadata only
896
897    Add info about the Crimea situation in zone1970.tab and zone.tab.
898    (Problem reported by Serhii Demediuk.)
899
900  Changes to code
901
902    zic's new -b option supports a way to control data bloat and to
903    test for year-2038 bugs in software that reads TZif files.
904    'zic -b fat' and 'zic -b slim' generate larger and smaller output;
905    for example, changing from fat to slim shrinks the Europe/London
906    file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
907    files represent the same set of timestamps and use the same TZif
908    format as documented in tzfile(5) and in Internet RFC 8536.
909    Fat format attempts to work around bugs or incompatibilities in
910    older software, notably software that mishandles 64-bit TZif data
911    or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
912    Slim format is more efficient and does not work around 64-bit bugs
913    or obsolete TZ strings.  Currently zic defaults to fat format
914    unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
915    out-of-the-box default is intended to change in future releases
916    as the buggy software often mishandles timestamps anyway.
917
918    zic no longer treats a set of rules ending in 2037 specially.
919    Previously, zic assumed that such a ruleset meant that future
920    timestamps could not be predicted, and therefore omitted a
921    POSIX-like TZ string in the TZif output.  The old behavior is no
922    longer needed for current tzdata, and caused problems with newlib
923    when used with older tzdata (reported by David Gauchard).
924
925    zic no longer generates some artifact transitions.  For example,
926    Europe/London no longer has a no-op transition in January 1996.
927
928  Changes to build procedure
929
930    tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
931    by a percent or so.
932
933  Changes to documentation and commentary
934
935    The Makefile now documents the POSIXRULES macro as being obsolete,
936    and similarly, zic's -p POSIXRULES option is now documented as
937    being obsolete.  Although the POSIXRULES feature still exists and
938    works as before, in practice it is rarely used for its intended
939    purpose, and it does not work either in the default reference
940    implementation (for timestamps after 2037) or in common
941    implementations such as GNU/Linux (for contemporary timestamps).
942    Since POSIXRULES was designed primarily as a temporary transition
943    facility for System V platforms that died off decades ago, it is
944    being decommissioned rather than institutionalized.
945
946    New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
947
948
949Release 2019a - 2019-03-25 22:01:33 -0700
950
951  Briefly:
952    Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
953    Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
954
955  Changes to past and future timestamps
956
957    Palestine will not start DST until 2019-03-30, instead of 2019-03-23 as
958    previously predicted.  Adjust our prediction by guessing that spring
959    transitions will be between 24 and 30 March, which matches recent practice
960    since 2016.  (Thanks to Even Scharning and Tim Parenti.)
961
962    Metlakatla ended its observance of Pacific standard time,
963    rejoining Alaska Time, on 2019-01-20 at 02:00.  (Thanks to Ryan
964    Stanley and Tim Parenti.)
965
966  Changes to past timestamps
967
968    Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
969    (Thanks to Alois Treindl and Isaac Starkman.)
970
971  Changes to time zone abbreviations
972
973    Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
974    of being a separate zone that generates the abbreviation "UCT",
975    which nowadays is typically a typo.  (Problem reported by Isiah
976    Meadows.)
977
978  Changes to code
979
980    zic now has an -r option to limit the time range of output data.
981    For example, 'zic -r @1000000000' limits the output data to
982    timestamps starting 1000000000 seconds after the Epoch.
983    This helps shrink output size and can be useful for applications
984    not needing the full timestamp history, such as TZDIST truncation;
985    see Internet RFC 8536 section 5.1.  (Inspired by a feature request
986    from Christopher Wong, helped along by bug reports from Wong and
987    from Tim Parenti.)
988
989  Changes to documentation
990
991    Mention Internet RFC 8536 (February 2019), which documents TZif.
992
993    tz-link.html now cites tzdata-meta
994    <https://tzdata-meta.timtimeonline.com/>.
995
996
997Release 2018i - 2018-12-30 11:05:43 -0800
998
999  Briefly:
1000    São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.
1001
1002  Changes to future timestamps
1003
1004    Due to a change in government, São Tomé and Príncipe switches back
1005    from +01 to +00 on 2019-01-01 at 02:00.  (Thanks to Vadim
1006    Nasardinov and Michael Deckers.)
1007
1008
1009Release 2018h - 2018-12-23 17:59:32 -0800
1010
1011  Briefly:
1012    Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
1013    New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
1014    Metlakatla, Alaska observes PST this winter only.
1015    Guess Morocco will continue to adjust clocks around Ramadan.
1016    Add predictions for Iran from 2038 through 2090.
1017
1018  Changes to future timestamps
1019
1020    Guess that Morocco will continue to fall back just before and
1021    spring forward just after Ramadan, the practice since 2012.
1022    (Thanks to Maamar Abdelkader.)  This means Morocco will observe
1023    negative DST during Ramadan in main and vanguard formats, and in
1024    rearguard format it stays in the +00 timezone and observes
1025    ordinary DST in all months other than Ramadan.  As before, extend
1026    this guesswork to the year 2037.  As a consequence, Morocco is
1027    scheduled to observe three DST transitions in some Gregorian years
1028    (e.g., 2033) due to the mismatch between the Gregorian and Islamic
1029    calendars.
1030
1031    The table of exact transitions for Iranian DST has been extended.
1032    It formerly cut off before the year 2038 in a nod to 32-bit time_t.
1033    It now cuts off before 2091 as there is doubt about how the Persian
1034    calendar will treat 2091.  This change predicts DST transitions in
1035    2038-9, 2042-3, and 2046-7 to occur one day later than previously
1036    predicted.  As before, post-cutoff transitions are approximated.
1037
1038  Changes to past and future timestamps
1039
1040    Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
1041    +05 on 2018-12-21.  This is a zone split as Qostanay (aka
1042    Kostanay) did not switch, so create a zone Asia/Qostanay.
1043
1044    Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
1045    It did not change clocks that day and remains on -08 this winter.
1046    (Thanks to Ryan Stanley.)  It will revert to the usual Alaska
1047    rules next spring, so this change affects only timestamps
1048    from 2018-11-04 through 2019-03-10.
1049
1050  Change to past timestamps
1051
1052    Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
1053    not 00:00.  I transcribed the time incorrectly from Shanks.
1054    (Thanks to Phake Nick.)
1055
1056    Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
1057    (Thanks to Phake Nick.)
1058
1059    Guam observed DST irregularly from 1959 through 1977.
1060    (Thanks to Phake Nick.)
1061
1062    Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
1063    10-01 changed standard time to +08:30 (not +08).  Its transition
1064    back to +08 after WWII was on 1945-09-15, not the previous day.
1065    Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
1066    (Thanks to Phake Nick, Steve Allen, and Joseph Myers.)  Also,
1067    its 1952 fallback was on 11-02 (not 10-25).
1068
1069    This release contains many changes to timestamps before 1946 due
1070    to Japanese possession or occupation of Pacific/Chuuk,
1071    Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
1072    Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
1073    (Thanks to Phake Nick.)
1074
1075    Assume that the Spanish East Indies was like the Philippines and
1076    observed American time until the end of 1844.  This affects
1077    Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.
1078
1079  Changes to past tm_isdst flags
1080
1081    For the recent Morocco change, the tm_isdst flag should be 1 from
1082    2018-10-27 00:00 to 2018-10-28 03:00.  (Thanks to Michael Deckers.)
1083    Give a URL to the official decree.  (Thanks to Matt Johnson.)
1084
1085
1086Release 2018g - 2018-10-26 22:22:45 -0700
1087
1088  Briefly:
1089    Morocco switches to permanent +01 on 2018-10-28.
1090
1091  Changes to future timestamps
1092
1093    Morocco switches from +00/+01 to permanent +01 effective 2018-10-28,
1094    so its clocks will not fall back as previously scheduled.
1095    (Thanks to Mohamed Essedik Najd and Brian Inglis.)
1096
1097  Changes to code
1098
1099    When generating TZif files with leap seconds, zic no longer uses a
1100    format that trips up older 32-bit clients, fixing a bug introduced
1101    in 2018f.  (Reported by Daniel Fischer.)  Also, the zic workaround
1102    for QTBUG-53071 now also works for TZif files with leap seconds.
1103
1104    The translator to rearguard format now rewrites the line
1105    "Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S" to
1106    "Rule Japan 1948 1951 - Sep Sun>=9  1:00 0 S".
1107    This caters to zic before 2007 and to Oracle TZUpdater 2.2.0
1108    and earlier.  (Reported by Christos Zoulas.)
1109
1110  Changes to past time zone abbreviations
1111
1112    Change HDT to HWT/HPT for WWII-era abbreviations in Hawaii.
1113    This reverts to 2011h, as the abbreviation change in 2011i was
1114    likely inadvertent.
1115
1116  Changes to documentation
1117
1118    tzfile.5 has new sections on interoperability issues.
1119
1120
1121Release 2018f - 2018-10-18 00:14:18 -0700
1122
1123  Briefly:
1124  Volgograd moves from +03 to +04 on 2018-10-28.
1125  Fiji ends DST 2019-01-13, not 2019-01-20.
1126  Most of Chile changes DST dates, effective 2019-04-06.
1127
1128  Changes to future timestamps
1129
1130    Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
1131    (Thanks to Alexander Fetisov and Stepan Golosunov.)
1132
1133    Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
1134    predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
1135    accordingly.
1136
1137    Most of Chile will end DST on the first Saturday in April at 24:00 mainland
1138    time, and resume DST on the first Saturday in September at 24:00 mainland
1139    time.  The changes are effective from 2019-04-06, and do not affect the
1140    Magallanes region modeled by America/Punta_Arenas.  (Thanks to Juan Correa
1141    and Tim Parenti.)  Adjust future predictions accordingly.
1142
1143  Changes to past timestamps
1144
1145    The 2018-05-05 North Korea 30-minute time zone change took place
1146    at 23:30 the previous day, not at 00:00 that day.
1147
1148    China's 1988 spring-forward transition was on April 17, not
1149    April 10.  Its DST transitions in 1986/91 were at 02:00, not 00:00.
1150    (Thanks to P Chan.)
1151
1152    Fix several issues for Macau before 1992.  Macau's pre-1904 LMT
1153    was off by 10 s.  Macau switched to +08 in 1904 not 1912, and
1154    temporarily switched to +09/+10 during World War II.  Macau
1155    observed DST in 1942/79, not 1961/80, and there were several
1156    errors for transition times and dates.  (Thanks to P Chan.)
1157
1158    The 1948-1951 fallback transitions in Japan were at 25:00 on
1159    September's second Saturday, not at 24:00.  (Thanks to Phake Nick.)
1160    zic turns this into 01:00 on the day after September's second
1161    Saturday, which is the best that POSIX or C platforms can do.
1162
1163    Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
1164    paper by Li Yu, replacing more-questionable data from Shanks.
1165
1166  Changes to time zone abbreviations
1167
1168    Use "PST" and "PDT" for Philippine time.  (Thanks to Paul Goyette.)
1169
1170  Changes to code
1171
1172    zic now always generates TZif files where time type 0 is used for
1173    timestamps before the first transition.  This simplifies the
1174    reading of TZif files and should not affect behavior of existing
1175    TZif readers because the same set of time types is used; only
1176    their internal indexes may have changed.  This affects only the
1177    legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
1178    EET, which previously used nonzero types for these timestamps.
1179
1180    Because of the type 0 change, zic no longer outputs a dummy
1181    transition at time -2**59 (before the Big Bang), as clients should
1182    no longer need this to handle historical timestamps correctly.
1183    This reverts a change introduced in 2013d and shrinks most TZif
1184    files by a few bytes.
1185
1186    zic now supports negative time-of-day in Rule and Leap lines, e.g.,
1187    "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
1188    occurs at 18:00 on the Saturday before the last Sunday in April.
1189    This behavior was documented in 2018a but the code did not
1190    entirely match the documentation.
1191
1192    localtime.c no longer requires at least one time type in TZif
1193    files that lack transitions or have a POSIX-style TZ string.  This
1194    future-proofs the code against possible future extensions to the
1195    format that would allow TZif files with POSIX-style TZ strings and
1196    without transitions or time types.
1197
1198    A read-access subscript error in localtime.c has been fixed.
1199    It could occur only in TZif files with timecnt == 0, something that
1200    does not happen in practice now but could happen in future versions.
1201
1202    localtime.c no longer ignores TZif POSIX-style TZ strings that
1203    specify only standard time.  Instead, these TZ strings now
1204    override the default time type for timestamps after the last
1205    transition (or for all timestamps if there are no transitions),
1206    just as DST strings specifying DST have always done.
1207
1208    leapseconds.awk now outputs "#updated" and "#expires" comments,
1209    and supports leap seconds at the ends of months other than June
1210    and December.  (Inspired by suggestions from Chris Woodbury.)
1211
1212  Changes to documentation
1213
1214    New restrictions: A Rule name must start with a character that
1215    is neither an ASCII digit nor "-" nor "+", and an unquoted name
1216    should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
1217    The latter restriction makes room for future extensions (a
1218    possibility noted by Tom Lane).
1219
1220    tzfile.5 now documents what time types apply before the first and
1221    after the last transition, if any.
1222
1223    Documentation now uses the spelling "timezone" for a TZ setting
1224    that determines timestamp history, and "time zone" for a
1225    geographic region currently sharing the same standard time.
1226
1227    The name "TZif" is now used for the tz binary data format.
1228
1229    tz-link.htm now mentions the A0 TimeZone Migration utilities.
1230    (Thanks to Aldrin Martoq for the link.)
1231
1232  Changes to build procedure
1233
1234    New 'make' target 'rearguard_tarballs' to build the rearguard
1235    tarball only.  This is a convenience on platforms that lack lzip
1236    if you want to build the rearguard tarball.  (Problem reported by
1237    Deborah Goldsmith.)
1238
1239    tzdata.zi is now more stable from release to release.  (Problem
1240    noted by Tom Lane.)  It is also a bit shorter.
1241
1242    tzdata.zi now can contain comment lines documenting configuration
1243    information, such as which data format was selected, which input
1244    files were used, and how leap seconds are treated.  (Problems
1245    noted by Lester Caine and Brian Inglis.)  If the Makefile defaults
1246    are used these comment lines are absent, for backward
1247    compatibility.  A redistributor intending to alter its copy of the
1248    files should also append "-LABEL" to the 'version' file's first
1249    line, where "LABEL" identifies the redistributor's change.
1250
1251
1252Release 2018e - 2018-05-01 23:42:51 -0700
1253
1254  Briefly:
1255
1256    North Korea switches back to +09 on 2018-05-05.
1257    The main format uses negative DST again, for Ireland etc.
1258    'make tarballs' now also builds a rearguard tarball.
1259    New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
1260
1261  Changes to past and future timestamps
1262
1263    North Korea switches back from +0830 to +09 on 2018-05-05.
1264    (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
1265    and Tim Parenti.)
1266
1267    Bring back the negative-DST changes of 2018a, except be more
1268    compatible with data parsers that do not support negative DST.
1269    Also, this now affects historical timestamps in Namibia and the
1270    former Czechoslovakia, not just Ireland.  The main format now uses
1271    negative DST to model timestamps in Europe/Dublin (from 1971 on),
1272    Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
1273    does not affect UT offsets, only time zone abbreviations and the
1274    tm_isdst flag.  Also, this does not affect rearguard or vanguard
1275    formats; effectively the main format now uses vanguard instead of
1276    rearguard format.  Data parsers that do not support negative DST
1277    can still use data from the rearguard tarball described below.
1278
1279  Changes to build procedure
1280
1281    The command 'make tarballs' now also builds the tarball
1282    tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
1283    except that it uses rearguard format intended for trailing-edge
1284    data parsers.
1285
1286  Changes to data format and to code
1287
1288    The SAVE column of Rule and Zone lines can now have an 's' or 'd'
1289    suffix, which specifies whether the adjusted time is standard time
1290    or daylight saving time.  If no suffix is given, daylight saving
1291    time is used if and only if the SAVE column is nonzero; this is
1292    the longstanding behavior.  Although this new feature is not used
1293    in tzdata, it could be used to specify the legal time in Namibia
1294    1994-2017, as opposed to the popular time (see below).
1295
1296  Changes to past timestamps
1297
1298    From 1994 through 2017 Namibia observed DST in winter, not summer.
1299    That is, it used negative DST, as Ireland still does.  This change
1300    does not affect UTC offsets; it affects only the tm_isdst flag and
1301    the abbreviation used during summer, which is now CAT, not WAST.
1302    Although (as noted by Michael Deckers) summer and winter time were
1303    both simply called "standard time" in Namibian law, in common
1304    practice winter time was considered to be DST (as noted by Stephen
1305    Colebourne).  The full effect of this change is only in vanguard
1306    and main format; in rearguard format, the tm_isdst flag is still
1307    zero in winter and nonzero in summer.
1308
1309    In 1946/7 Czechoslovakia also observed negative DST in winter.
1310    The full effect of this change is only in vanguard and main
1311    formats; in rearguard format, it is modeled as plain GMT without
1312    daylight saving.  Also, the dates of some 1944/5 DST transitions
1313    in Czechoslovakia have been changed.
1314
1315
1316Release 2018d - 2018-03-22 07:05:46 -0700
1317
1318  Briefly:
1319
1320  Palestine starts DST a week earlier in 2018.
1321  Add support for vanguard and rearguard data consumers.
1322  Add subsecond precision to source data format, though not to data.
1323
1324  Changes to future timestamps
1325
1326    In 2018, Palestine starts DST on March 24, not March 31.
1327    Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
1328
1329  Changes to past and future timestamps
1330
1331    Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
1332    at 04:00.  (Thanks to Steffen Thorsen.)
1333
1334  Changes to past timestamps
1335
1336    Historical transitions for Uruguay, represented by
1337    America/Montevideo, have been updated per official legal documents,
1338    replacing previous data mainly originating from the inventions of
1339    Shanks & Pottenger.  This has resulted in adjustments ranging from
1340    30 to 90 minutes in either direction over at least two dozen
1341    distinct periods ranging from one day to several years in length.
1342    A mere handful of pre-1991 transitions are unaffected; data since
1343    then has come from more reliable contemporaneous reporting.  These
1344    changes affect various timestamps in 1920-1923, 1936, 1939,
1345    1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
1346    Additionally, Uruguay's pre-standard-time UT offset has been
1347    adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
1348    match the location of the Observatory of the National Meteorological
1349    Institute in Montevideo.
1350    (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
1351
1352    East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
1353    (Thanks to Kerry Shetline.)
1354
1355    Fix the 1912-01-01 transition for Portugal and its colonies.
1356    This transition was at 00:00 according to the new UT offset, not
1357    according to the old one.  Also assume that Cape Verde switched on
1358    the same date as the rest, not in 1907.  This affects
1359    Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
1360    Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
1361    (Thanks to Michael Deckers.)
1362
1363    Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
1364    Turks & Caicos.
1365
1366  Changes to past time zone abbreviations
1367
1368    MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
1369    is no clock change associated with the transition.
1370
1371  Changes to build procedure
1372
1373    The new DATAFORM macro in the Makefile lets the installer choose
1374    among three source data formats.  The idea is to lessen downstream
1375    disruption when data formats are improved.
1376
1377    * DATAFORM=vanguard installs from the latest, bleeding-edge
1378      format.  DATAFORM=main (the default) installs from the format
1379      used in the 'africa' etc. files.  DATAFORM=rearguard installs
1380      from a trailing-edge format.  Eventually, elements of today's
1381      vanguard format should move to the main format, and similarly
1382      the main format's features should eventually move to the
1383      rearguard format.
1384
1385    * In the current version, the main and rearguard formats are
1386      identical and match that of 2018c, so this change does not
1387      affect default behavior.  The vanguard format currently contains
1388      one feature not in the main format: negative SAVE values.  This
1389      improves support for Ireland, which uses Irish Standard Time
1390      (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
1391      supported negative SAVE values for decades, and this feature
1392      should move to the main format soon.  However, it will not move
1393      to the rearguard format for quite some time because some
1394      downstream parsers do not support it.
1395
1396    * The build procedure constructs three files vanguard.zi, main.zi,
1397      and rearguard.zi, one for each format.  Although the files
1398      represent essentially the same data, they may have minor
1399      discrepancies that users are not likely to notice.  The files
1400      are intended for downstream data consumers and are not
1401      installed.  Zoneinfo parsers that do not support negative SAVE values
1402      should start using rearguard.zi, so that they will be unaffected
1403      when the negative-DST feature moves from vanguard to main.
1404      Bleeding-edge Zoneinfo parsers that support the new features
1405      already can use vanguard.zi; in this respect, current tzcode is
1406      bleeding-edge.
1407
1408    The Makefile should now be safe for parallelized builds, and 'make
1409    -j to2050new.tzs' is now much faster on a multiprocessor host
1410    with GNU Make.
1411
1412    When built with -DSUPPRESS_TZDIR, the tzcode library no longer
1413    prepends TZDIR/ to file names that do not begin with '/'.  This is
1414    not recommended for general use, due to its security implications.
1415    (From a suggestion by Manuela Friedrich.)
1416
1417  Changes to code
1418
1419    zic now accepts subsecond precision in expressions like
1420    00:19:32.13, which is approximately the legal time of the
1421    Netherlands from 1835 to 1937.  However, because it is
1422    questionable whether the few recorded uses of non-integer offsets
1423    had subsecond precision in practice, there are no plans for tzdata
1424    to use this feature.  (Thanks to Steve Allen for pointing out
1425    the limitations of historical data in this area.)
1426
1427    The code is a bit more portable to MS-Windows.  Installers can
1428    compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
1429    reserve identifiers like 'localtime'.  (Thanks to Manuela
1430    Friedrich.)
1431
1432  Changes to documentation and commentary
1433
1434    theory.html now outlines tzdb's extensions to POSIX's model for
1435    civil time, and has a section "POSIX features no longer needed"
1436    that lists POSIX API components that are now vestigial.
1437    (From suggestions by Steve Summit.)  It also better distinguishes
1438    time zones from tz regions.  (From a suggestion by Guy Harris.)
1439
1440    Commentary is now more consistent about using the phrase "daylight
1441    saving time", to match the C name tm_isdst.  Daylight saving time
1442    need not occur in summer, and need not have a positive offset from
1443    standard time.
1444
1445    Commentary about historical transitions in Uruguay has been expanded
1446    with links to many relevant legal documents.
1447    (Thanks to Tim Parenti.)
1448
1449    Commentary now uses some non-ASCII characters with Unicode value
1450    less than U+0100, as they can be useful and should work even with
1451    older editors such as XEmacs.
1452
1453
1454Release 2018c - 2018-01-22 23:00:44 -0800
1455
1456  Briefly:
1457  Revert Irish changes that relied on negative SAVE values.
1458
1459  Changes to tm_isdst
1460
1461    Revert the 2018a change to Europe/Dublin.  As before, this change
1462    does not affect UT offsets or abbreviations; it affects only
1463    whether timestamps are considered to be standard time or
1464    daylight-saving time, as expressed in the tm_isdst flag of C's
1465    struct tm type.  This reversion is intended to be a temporary
1466    workaround for problems discovered with downstream uses of
1467    releases 2018a and 2018b, which implemented Irish time by using
1468    negative SAVE values in the Eire rules of the 'europe' file.
1469    Although negative SAVE values have been part of tzcode for many
1470    years and are supported by many platforms, they were not
1471    documented before 2018a and ICU and OpenJDK do not currently
1472    support them.  A mechanism to export data to platforms lacking
1473    support for negative DST is planned to be developed before the
1474    change is reapplied.  (Problems reported by Deborah Goldsmith and
1475    Stephen Colebourne.)
1476
1477  Changes to past timestamps
1478
1479    Japanese DST transitions (1948-1951) were Sundays at 00:00, not
1480    Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
1481
1482  Changes to build procedure
1483
1484    The build procedure now works around mawk 1.3.3's lack of support
1485    for character class expressions.  (Problem reported by Ohyama.)
1486
1487
1488Release 2018b - 2018-01-17 23:24:48 -0800
1489
1490  Briefly:
1491  Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
1492
1493  Changes to build procedure
1494
1495    The distribution now contains the file 'pacificnew' again.
1496    This file was inadvertently omitted in the 2018a distribution.
1497    (Problem reported by Matias Fonzo.)
1498
1499
1500Release 2018a - 2018-01-12 22:29:21 -0800
1501
1502  Briefly:
1503  São Tomé and Príncipe switched from +00 to +01.
1504  Brazil's DST will now start on November's first Sunday.
1505  Ireland's standard time is now in the summer, not the winter.
1506  Use Debian-style installation locations, instead of 4.3BSD-style.
1507  New zic option -t.
1508
1509  Changes to past and future timestamps
1510
1511    São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
1512    01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
1513
1514  Changes to future timestamps
1515
1516    Starting in 2018 southern Brazil will begin DST on November's
1517    first Sunday instead of October's third Sunday.  (Thanks to
1518    Steffen Thorsen.)
1519
1520  Changes to past timestamps
1521
1522    A discrepancy of 4 s in timestamps before 1931 in South Sudan has
1523    been corrected.  The 'backzone' and 'zone.tab' files did not agree
1524    with the 'africa' and 'zone1970.tab' files.  (Problem reported by
1525    Michael Deckers.)
1526
1527    The abbreviation invented for Bolivia Summer Time (1931-2) is now
1528    BST instead of BOST, to be more consistent with the convention
1529    used for Latvian Summer Time (1918-9) and for British Summer Time.
1530
1531  Changes to tm_isdst
1532
1533    Change Europe/Dublin so that it observes Irish Standard Time (UT
1534    +01) in summer and GMT (as negative daylight-saving) in winter,
1535    instead of observing standard time (GMT) in winter and Irish
1536    Summer Time (UT +01) in summer.  This change does not affect UT
1537    offsets or abbreviations; it affects only whether timestamps are
1538    considered to be standard time or daylight-saving time, as
1539    expressed in the tm_isdst flag of C's struct tm type.
1540    (Discrepancy noted by Derick Rethans.)
1541
1542  Changes to build procedure
1543
1544    The default installation locations have been changed to mostly
1545    match Debian circa 2017, instead of being designed as an add-on to
1546    4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
1547    TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
1548    USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
1549    locations more precisely.  (This responds to suggestions from
1550    Brian Inglis and from Steve Summit.)
1551
1552    The default installation procedure no longer creates the
1553    backward-compatibility link US/Pacific-New, which causes
1554    confusion during user setup (e.g., see Debian bug 815200).
1555    Use 'make BACKWARD="backward pacificnew"' to create the link
1556    anyway, for now.  Eventually we plan to remove the link entirely.
1557
1558    tzdata.zi now contains a version-number comment.
1559    (Suggested by Tom Lane.)
1560
1561    The Makefile now quotes values like BACKWARD more carefully when
1562    passing them to the shell.  (Problem reported by Zefram.)
1563
1564    Builders no longer need to specify -DHAVE_SNPRINTF on platforms
1565    that have snprintf and use pre-C99 compilers.  (Problem reported
1566    by Jon Skeet.)
1567
1568  Changes to code
1569
1570    zic has a new option -t FILE that specifies the location of the
1571    file that determines local time when TZ is unset.  The default for
1572    this location can be configured via the new TZDEFAULT makefile
1573    macro, which defaults to /etc/localtime.
1574
1575    Diagnostics and commentary now distinguish UT from UTC more
1576    carefully; see theory.html for more information about UT vs UTC.
1577
1578    zic has been ported to GCC 8's -Wstringop-truncation option.
1579    (Problem reported by Martin Sebor.)
1580
1581  Changes to documentation and commentary
1582
1583    The zic man page now documents the longstanding behavior that
1584    times and years can be out of the usual range, with negative times
1585    counting backwards from midnight and with year 0 preceding year 1.
1586    (Problem reported by Michael Deckers.)
1587
1588    The theory.html file now mentions the POSIX limit of six chars
1589    per abbreviation, and lists alphabetic abbreviations used.
1590
1591    The files tz-art.htm and tz-link.htm have been renamed to
1592    tz-art.html and tz-link.html, respectively, for consistency with
1593    other file names and to simplify web server configuration.
1594
1595
1596Release 2017c - 2017-10-20 14:49:34 -0700
1597
1598  Briefly:
1599  Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
1600  Fiji ends DST 2018-01-14, not 2018-01-21.
1601  Namibia switches from +01/+02 to +02 on 2018-04-01.
1602  Sudan switches from +03 to +02 on 2017-11-01.
1603  Tonga likely switches from +13/+14 to +13 on 2017-11-05.
1604  Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
1605  A new file tzdata.zi now holds a small text copy of all data.
1606  The zic input format has been regularized slightly.
1607
1608  Changes to future timestamps
1609
1610    Northern Cyprus has decided to resume EU rules starting
1611    2017-10-29, thus reinstituting winter time.
1612
1613    Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
1614    predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
1615    accordingly.
1616
1617    Namibia will switch from +01 with DST to +02 all year on
1618    2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
1619    at 02:00.  (Thanks to Steffen Thorsen.)
1620
1621    Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
1622    Atyya and Yahia Abdalla.)  South Sudan is not switching, so
1623    Africa/Juba is no longer a link to Africa/Khartoum.
1624
1625    Tonga has likely ended its experiment with DST, and will not
1626    adjust its clocks on 2017-11-05.  Although Tonga has not announced
1627    whether it will continue to observe DST, the IATA is assuming that
1628    it will not.  (Thanks to David Wade.)
1629
1630    Turks & Caicos will switch from -04 all year to -05 with US DST on
1631    2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
1632    at 02:00.  (Thanks to Steffen Thorsen.)
1633
1634  Changes to past timestamps
1635
1636    Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
1637    (Thanks to Arthur David Olson.)
1638
1639    Detroit did not observe DST in 1967.
1640
1641    Use railway time for Asia/Kolkata before 1941, by switching to
1642    Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
1643    1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
1644
1645    Europe/Dublin's 1946 and 1947 fallback transitions occurred at
1646    02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
1647
1648    Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
1649    American time in 1892, not 1879.  (Thanks to Michael Deckers.)
1650
1651    Adjust the 1867 transition in Alaska to better reflect the
1652    historical record, by changing it to occur on 1867-10-18 at 15:30
1653    Sitka time rather than at the start of 1867-10-17 local time.
1654    Although strictly speaking this is accurate only for Sitka,
1655    the rest of Alaska's blanks need to be filled in somehow.
1656
1657    Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
1658    (Thanks to Michael Deckers.)
1659
1660    Add 7 s to the UT offset in Asia/Yangon before 1920.
1661
1662  Changes to zone names
1663
1664    Remove Canada/East-Saskatchewan from the 'backward' file, as it
1665    exceeded the 14-character limit and was an unused misnomer anyway.
1666
1667  Changes to build procedure
1668
1669    To support applications that prefer to read time zone data in text
1670    form, two zic input files tzdata.zi and leapseconds are now
1671    installed by default.  The commands 'zic tzdata.zi' and 'zic -L
1672    leapseconds tzdata.zi' can reproduce the tzdata binary files
1673    without and with leap seconds, respectively.  To prevent these two
1674    new files from being installed, use 'make TZDATA_TEXT=', and to
1675    suppress leap seconds from the tzdata text installation, use 'make
1676    TZDATA_TEXT=tzdata.zi'.
1677
1678    'make BACKWARD=' now suppresses backward-compatibility names
1679    like 'US/Pacific' that are defined in the 'backward' and
1680    'pacificnew' files.
1681
1682    'make check' now works on systems that lack a UTF-8 locale,
1683    or that lack the nsgmls program.  Set UTF8_LOCALE to configure
1684    the name of a UTF-8 locale, if you have one.
1685
1686    Y2K runtime checks are no longer enabled by default.  Add
1687    -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
1688    adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
1689    to disable them.  (New name suggested by Brian Inglis.)
1690
1691    The build procedure for zdump now works on AIX 7.1.
1692    (Problem reported by Kees Dekker.)
1693
1694  Changes to code
1695
1696    zic and the reference runtime now reject multiple leap seconds
1697    within 28 days of each other, or leap seconds before the Epoch.
1698    As a result, support for double leap seconds, which was
1699    obsolescent and undocumented, has been removed.  Double leap
1700    seconds were an error in the C89 standard; they have never existed
1701    in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
1702    noticing glitches in the code that uncovered this problem.)
1703
1704    zic now warns about use of the obsolescent and undocumented -y
1705    option, and about use of the obsolescent TYPE field of Rule lines.
1706
1707    zic now allows unambiguous abbreviations like "Sa" and "Su" for
1708    weekdays; formerly it rejected them due to a bug.  Conversely, zic
1709    no longer considers non-prefixes to be abbreviations; for example,
1710    it no longer accepts "lF" as an abbreviation for "lastFriday".
1711    Also, zic warns about the undocumented usage with a "last-"
1712    prefix, e.g., "last-Fri".
1713
1714    Similarly, zic now accepts the unambiguous abbreviation "L" for
1715    "Link" in ordinary context and for "Leap" in leap-second context.
1716    Conversely, zic no longer accepts non-prefixes such as "La" as
1717    abbreviations for words like "Leap".
1718
1719    zic no longer accepts leap second lines in ordinary input, or
1720    ordinary lines in leap second input.  Formerly, zic sometimes
1721    warned about this undocumented usage and handled it incorrectly.
1722
1723    The new macro HAVE_TZNAME governs whether the tzname external
1724    variable is exported, instead of USG_COMPAT.  USG_COMPAT now
1725    governs only the external variables "timezone" and "daylight".
1726    This change is needed because the three variables are not in the
1727    same category: although POSIX requires tzname, it specifies the
1728    other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
1729    if not defined, the code attempts to guess it from other macros.
1730
1731    localtime.c and difftime.c no longer require stdio.h, and .c files
1732    other than zic.c no longer require sys/wait.h.
1733
1734    zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
1735
1736    Calculation of time_t extrema works around a bug in GCC 4.8.4
1737    (Reported by Stan Shebs and Joseph Myers.)
1738
1739    zic.c no longer mistranslates formats of line numbers in non-English
1740    locales.  (Problem reported by Benno Schulenberg.)
1741
1742    Several minor changes have been made to the code to make it a
1743    bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
1744    Dekker for reporting the problems.)
1745
1746  Changes to documentation and commentary
1747
1748    The two new files 'theory.html' and 'calendars' contain the
1749    contents of the removed file 'Theory'.  The goal is to document
1750    tzdb theory more accessibly.
1751
1752    The zic man page now documents abbreviation rules.
1753
1754    tz-link.htm now covers how to apply tzdata changes to clients.
1755    (Thanks to Jorge Fábregas for the AIX link.)  It also mentions MySQL.
1756
1757    The leap-seconds.list URL has been updated to something that is
1758    more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
1759
1760Release 2017b - 2017-03-17 07:30:38 -0700
1761
1762  Briefly: Haiti has resumed DST.
1763
1764  Changes to past and future timestamps
1765
1766    Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
1767
1768  Changes to past timestamps
1769
1770    Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
1771
1772    Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
1773    is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
1774
1775  Changes to code
1776
1777    The reference localtime implementation now falls back on the
1778    current US daylight-saving transition rules rather than the
1779    1987-2006 rules.  This fallback occurs only when (1) the TZ
1780    environment variable has a value like "AST4ADT" that asks
1781    for daylight saving time but does not specify the rules, (2) there
1782    is no file by that name, and (3) the TZDEFRULES file cannot be
1783    loaded.  (Thanks to Tom Lane.)
1784
1785
1786Release 2017a - 2017-02-28 00:05:36 -0800
1787
1788  Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
1789  discontinues DST.
1790
1791  Changes to future timestamps
1792
1793    Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
1794
1795    Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
1796    Its clocks diverge from America/Santiago starting 2017-05-13 at
1797    23:00, hiving off a new zone America/Punta_Arenas.  Although the
1798    Chilean government says this change expires in May 2019, for now
1799    assume it's permanent.  (Thanks to Juan Correa and Deborah
1800    Goldsmith.)  This also affects Antarctica/Palmer.
1801
1802  Changes to past timestamps
1803
1804    Fix many entries for historical timestamps for Europe/Madrid
1805    before 1979, to agree with tables compiled by Pere Planesas of the
1806    National Astronomical Observatory of Spain.  As a side effect,
1807    this changes some timestamps for Africa/Ceuta before 1929, which
1808    are probably guesswork anyway.  (Thanks to Steve Allen and
1809    Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
1810    correcting the 1901 transition.)
1811
1812    Ecuador observed DST from 1992-11-28 to 1993-02-05.
1813    (Thanks to Alois Treindl.)
1814
1815    Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
1816    (Thanks to Stepan Golosunov.)
1817
1818  Changes to past and future time zone abbreviations
1819
1820    Switch to numeric time zone abbreviations for South America, as
1821    part of the ongoing project of removing invented abbreviations.
1822    This avoids the need to invent an abbreviation for the new Chilean
1823    new zone.  Similarly, switch from invented to numeric time zone
1824    abbreviations for Afghanistan, American Samoa, the Azores,
1825    Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
1826    Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
1827    Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
1828    Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
1829    the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
1830    Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
1831    Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
1832    Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
1833    Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
1834    Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
1835    for half-hour daylight saving time in Belize before 1944 and in
1836    the Dominican Republic before 1975; and for Canary Islands before
1837    1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
1838    Indian Summer Time before 1942, for Indonesia before around 1964,
1839    for Kenya before 1960, for Liberia before 1973, for Madeira before
1840    1967, for Namibia before 1943, for the Netherlands in 1937-9, for
1841    Pakistan before 1971, for Western Sahara before 1977, and for
1842    Zaporozhye in 1880-1924.
1843
1844    For Alaska time from 1900 through 1967, instead of "CAT" use the
1845    abbreviation "AST", the abbreviation commonly used at the time
1846    (Atlantic Standard Time had not been standardized yet).  Use "AWT"
1847    and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
1848
1849    Use "CST" and "CDT" instead of invented abbreviations for Macau
1850    before 1999 and Taiwan before 1938, and use "JST" instead of the
1851    invented abbreviation "JCST" for Japan and Korea before 1938.
1852
1853  Change to database entry category
1854
1855    Move the Pacific/Johnston link from 'australasia' to 'backward',
1856    since Johnston is now uninhabited.
1857
1858  Changes to code
1859
1860    zic no longer mishandles some transitions in January 2038 when it
1861    attempts to work around Qt bug 53071.  This fixes a bug affecting
1862    Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
1863    now contains a workaround, useful when loading a file generated by
1864    a buggy zic.  (Problem and localtime.c fix reported by Bradley
1865    White.)
1866
1867    zdump -i now outputs non-hour numeric time zone abbreviations
1868    without a colon, e.g., "+0530" rather than "+05:30".  This agrees
1869    with zic %z and with common practice, and simplifies auditing of
1870    zdump output.
1871
1872    zdump is now buildable again with -DUSE_LTZ=0.
1873    (Problem reported by Joseph Myers.)
1874
1875    zdump.c now always includes private.h, to avoid code duplication
1876    with private.h.  (Problem reported by Kees Dekker.)
1877
1878    localtime.c no longer mishandles early or late timestamps
1879    when TZ is set to a POSIX-style string that specifies DST.
1880    (Problem reported by Kees Dekker.)
1881
1882    date and strftime now cause %z to generate "-0000" instead of
1883    "+0000" when the UT offset is zero and the time zone abbreviation
1884    begins with "-".
1885
1886  Changes to documentation and commentary
1887
1888    The 'Theory' file now better documents choice of historical time
1889    zone abbreviations.  (Problems reported by Michael Deckers.)
1890
1891    tz-link.htm now covers leap smearing, which is popular in clouds.
1892
1893
1894Release 2016j - 2016-11-22 23:17:13 -0800
1895
1896  Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
1897
1898  Changes to future timestamps
1899
1900    Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
1901    This hives off a new zone Europe/Saratov from Europe/Volgograd.
1902    (Thanks to Yuri Konotopov and Stepan Golosunov.)
1903
1904  Changes to past timestamps
1905
1906    The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
1907    Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
1908    1999, not fall 1994.  (Thanks to Stepan Golosunov.)
1909
1910  Changes to past time zone abbreviations
1911
1912    Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
1913    summer time before 1948.  The old use of "EET" was a typo.
1914
1915  Changes to code
1916
1917    zic no longer mishandles file systems that lack hard links, fixing
1918    bugs introduced in 2016g.  (Problems reported by Tom Lane.)
1919    Also, when the destination already contains symbolic links, zic
1920    should now work better on systems where the 'link' system call
1921    does not follow symbolic links.
1922
1923  Changes to documentation and commentary
1924
1925    tz-link.htm now documents the relationship between release version
1926    numbers and development-repository commit tags.  (Suggested by
1927    Paul Koning.)
1928
1929    The 'Theory' file now documents UT.
1930
1931    iso3166.tab now accents "Curaçao", and commentary now mentions
1932    the names "Cabo Verde" and "Czechia".  (Thanks to Jiří Boháč.)
1933
1934
1935Release 2016i - 2016-11-01 23:19:52 -0700
1936
1937  Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
1938  reintroduces DST on 2016-11-06.
1939
1940  Changes to future timestamps
1941
1942    Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
1943    2017-01-15 at 03:00.  Assume future observances in Tonga will be
1944    from the first Sunday in November through the third Sunday in
1945    January, like Fiji.  (Thanks to Pulu ʻAnau.)  Switch to numeric
1946    time zone abbreviations for this zone.
1947
1948  Changes to past and future timestamps
1949
1950    Northern Cyprus is now +03 year round, causing a split in Cyprus
1951    time zones starting 2016-10-30 at 04:00.  This creates a zone
1952    Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
1953
1954    Antarctica/Casey switched from +08 to +11 on 2016-10-22.
1955    (Thanks to Steffen Thorsen.)
1956
1957  Changes to past timestamps
1958
1959    Several corrections were made for pre-1975 timestamps in Italy.
1960    These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
1961    Europe/Vatican.
1962
1963    First, the 1893-11-01 00:00 transition in Italy used the new UT
1964    offset (+01), not the old (+00:49:56).  (Thanks to Michael
1965    Deckers.)
1966
1967    Second, rules for daylight saving in Italy were changed to agree
1968    with Italy's National Institute of Metrological Research (INRiM)
1969    except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
1970    Inglis, and Michael Deckers):
1971
1972      The 1916-06-03 transition was at 24:00, not 00:00.
1973
1974      The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
1975      00:00, not 01:00.
1976
1977      The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
1978      01:00.
1979
1980      The 1944-09-17 transition was at 03:00, not 01:00.  This
1981      particular change is taken from Italian law as INRiM's table,
1982      (which says 02:00) appears to have a typo here.  Also, keep the
1983      1944-04-03 transition for Europe/Rome, as Rome was controlled by
1984      Germany then.
1985
1986      The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
1987      not 00:00.
1988
1989  Changes to code
1990
1991    The code should now be buildable on AmigaOS merely by setting the
1992    appropriate Makefile variables.  (From a patch by Carsten Larsen.)
1993
1994
1995Release 2016h - 2016-10-19 23:17:57 -0700
1996
1997  Changes to future timestamps
1998
1999    Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
2000    2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
2001    future fall transitions will be on the last Saturday of October
2002    at 01:00, which is consistent with predicted spring transitions
2003    on the last Saturday of March.  (Thanks to Tim Parenti.)
2004
2005  Changes to past timestamps
2006
2007    In Turkey, transitions in 1986-1990 were at 01:00 standard time
2008    not at 02:00, and the spring 1994 transition was on March 20, not
2009    March 27.  (Thanks to Kıvanç Yazan.)
2010
2011  Changes to past and future time zone abbreviations
2012
2013    Asia/Colombo now uses numeric time zone abbreviations like "+0530"
2014    instead of alphabetic ones like "IST" and "LKT".  Various
2015    English-language sources use "IST", "LKT" and "SLST", with no
2016    working consensus.  (Usage of "SLST" mentioned by Sadika
2017    Sumanapala.)
2018
2019  Changes to code
2020
2021    zic no longer mishandles relativizing file names when creating
2022    symbolic links like /etc/localtime, when these symbolic links
2023    are outside the usual directory hierarchy.  This fixes a bug
2024    introduced in 2016g.  (Problem reported by Andreas Stieger.)
2025
2026  Changes to build procedure
2027
2028    New rules 'traditional_tarballs' and 'traditional_signatures' for
2029    building just the traditional-format distribution.  (Requested by
2030    Deborah Goldsmith.)
2031
2032    The file 'version' is now put into the tzdata tarball too.
2033    (Requested by Howard Hinnant.)
2034
2035  Changes to documentation and commentary
2036
2037    The 'Theory' file now has a section on interface stability.
2038    (Requested by Paul Koning.)  It also mentions features like
2039    tm_zone and localtime_rz that have long been supported by the
2040    reference code.
2041
2042    tz-link.htm has improved coverage of time zone boundaries suitable
2043    for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
2044    Johnson.)
2045
2046    The US commentary now mentions Allen and the "day of two noons".
2047
2048    The Fiji commentary mentions the government's 2016-10-03 press
2049    release.  (Thanks to Raymond Kumar.)
2050
2051
2052Release 2016g - 2016-09-13 08:56:38 -0700
2053
2054  Changes to future timestamps
2055
2056    Turkey switched from EET/EEST (+02/+03) to permanent +03,
2057    effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
2058    than an invented abbreviation for the new time.
2059
2060    New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
2061    (Thanks to Tim Parenti.)
2062
2063  Changes to past timestamps
2064
2065    For America/Los_Angeles, spring-forward transition times have been
2066    corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
2067    1950-1966.
2068
2069    For zones using Soviet time on 1919-07-01, transitions to UT-based
2070    time were at 00:00 UT, not at 02:00 local time.  The affected
2071    zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
2072    Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
2073
2074  Changes to past and future time zone abbreviations
2075
2076    The Factory zone now uses the time zone abbreviation -00 instead
2077    of a long English-language string, as -00 is now the normal way to
2078    represent an undefined time zone.
2079
2080    Several zones in Antarctica and the former Soviet Union, along
2081    with zones intended for ships at sea that cannot use POSIX TZ
2082    strings, now use numeric time zone abbreviations instead of
2083    invented or obsolete alphanumeric abbreviations.  The affected
2084    zones are Antarctica/Casey, Antarctica/Davis,
2085    Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
2086    Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
2087    Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
2088    Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
2089    Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
2090    Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
2091    Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
2092    Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
2093    Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
2094    Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
2095    Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
2096    Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
2097    Europe/Minsk, Europe/Samara, Europe/Volgograd, and
2098    Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
2099    was replaced by +05, whereas MSK and MSD were kept as they are not
2100    our invention and are widely used.
2101
2102  Changes to zone names
2103
2104    Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
2105    (Thanks to David Massoud.)
2106
2107  Changes to code
2108
2109    zic no longer generates binary files containing POSIX TZ-like
2110    strings that disagree with the local time type after the last
2111    explicit transition in the data.  This fixes a bug with
2112    Africa/Casablanca and Africa/El_Aaiun in some year-2037 timestamps
2113    on the reference platform.  (Thanks to Alexander Belopolsky for
2114    reporting the bug and suggesting a way forward.)
2115
2116    If the installed localtime and/or posixrules files are symbolic
2117    links, zic now keeps them symbolic links when updating them, for
2118    compatibility with platforms like OpenSUSE where other programs
2119    configure these files as symlinks.
2120
2121    zic now avoids hard linking to symbolic links, avoids some
2122    unnecessary mkdir and stat system calls, and uses shorter file
2123    names internally.
2124
2125    zdump has a new -i option to generate transitions in a
2126    more-compact but still human-readable format.  This option is
2127    experimental, and the output format may change in future versions.
2128    (Thanks to Jon Skeet for suggesting that an option was needed,
2129    and thanks to Tim Parenti and Chris Rovick for further comments.)
2130
2131  Changes to build procedure
2132
2133    An experimental distribution format is available, in addition
2134    to the traditional format which will continue to be distributed.
2135    The new format is a tarball tzdb-VERSION.tar.lz with signature
2136    file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
2137    tzdb-VERSION containing the code and data of the traditional
2138    two-tarball format, along with extra data that may be useful.
2139    (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
2140    for comments about the experimental format.)
2141
2142    The release version number is now more accurate in the usual case
2143    where releases are built from a Git repository.  For example, if
2144    23 commits and some working-file changes have been made since
2145    release 2016g, the version number is now something like
2146    '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
2147    Tagged releases use the same version number format as before,
2148    e.g., '2016g'.  To support the more-accurate version number, its
2149    specification has moved from a line in the Makefile to a new
2150    source file 'version'.
2151
2152    The experimental distribution contains a file to2050.tzs that
2153    contains what should be the output of 'zdump -i -c 2050' on
2154    primary zones.  If this file is available, 'make check' now checks
2155    that zdump generates this output.
2156
2157    'make check_web' now works on Fedora-like distributions.
2158
2159  Changes to documentation and commentary
2160
2161    tzfile.5 now documents the new restriction on POSIX TZ-like
2162    strings that is now implemented by zic.
2163
2164    Comments now cite URLs for some 1917-1921 Russian DST decrees.
2165    (Thanks to Alexander Belopolsky.)
2166
2167    tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
2168    (thanks to Meno Hochschild) and ThreeTen-Extra, and its
2169    description of Java 8 has been brought up to date (thanks to
2170    Stephen Colebourne).  Its description of local time on Mars has
2171    been updated to match current practice, and URLs have been updated
2172    and some obsolete ones removed.
2173
2174
2175Release 2016f - 2016-07-05 16:26:51 +0200
2176
2177  Changes affecting future timestamps
2178
2179    The Egyptian government changed its mind on short notice, and
2180    Africa/Cairo will not introduce DST starting 2016-07-07 after all.
2181    (Thanks to Mina Samuel.)
2182
2183    Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
2184    (Thanks to Stepan Golosunov.)
2185
2186  Changes to past and future timestamps
2187
2188    Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
2189    abbreviations instead of invented ones.
2190
2191  Changes affecting past timestamps
2192
2193    Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
2194    (Thanks to Stepan Golosunov.)
2195
2196
2197Release 2016e - 2016-06-14 08:46:16 -0700
2198
2199  Changes affecting future timestamps
2200
2201    Africa/Cairo observes DST in 2016 from July 7 to the end of October.
2202    Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
2203    For future years, guess April's last Thursday to October's last
2204    Thursday except for Ramadan.
2205
2206  Changes affecting past timestamps
2207
2208    Locations while uninhabited now use '-00', not 'zzz', as a
2209    placeholder time zone abbreviation.  This is inspired by Internet
2210    RFC 3339 and is more consistent with numeric time zone
2211    abbreviations already used elsewhere.  The change affects several
2212    arctic and antarctic locations, e.g., America/Cambridge_Bay before
2213    1920 and Antarctica/Troll before 2005.
2214
2215    Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
2216    at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
2217
2218  Changes to code
2219
2220    zic now outputs a dummy transition at time 2**31 - 1 in zones
2221    whose POSIX-style TZ strings contain a '<'.  This mostly works
2222    around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
2223    (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
2224
2225  Changes affecting documentation and commentary
2226
2227    tz-link.htm says why governments should give plenty of notice for
2228    time zone or DST changes, and refers to Matt Johnson's blog post.
2229
2230    tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
2231
2232
2233Release 2016d - 2016-04-17 22:50:29 -0700
2234
2235  Changes affecting future timestamps
2236
2237    America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
2238    (Thanks to Alexander Krivenyshev for the heads-up.)
2239
2240    Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
2241    (Thanks to Alexander Krivenyshev and Matt Johnson.)
2242
2243    New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
2244    Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
2245    at 02:00.  (Thanks to Stepan Golosunov.)
2246
2247  Changes affecting past timestamps
2248
2249    New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
2250    Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
2251    1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
2252    the same change.  (Thanks to Stepan Golosunov.)
2253
2254    Russia and nearby locations had daylight-saving transitions on
2255    1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
2256    1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
2257    Golosunov.)
2258
2259    Many corrections to historical time in Kazakhstan from 1991
2260    through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
2261    invented time zone abbreviations with numeric abbreviations.
2262
2263  Changes to commentary
2264
2265    Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
2266
2267
2268Release 2016c - 2016-03-23 00:51:27 -0700
2269
2270  Changes affecting future timestamps
2271
2272    Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
2273
2274    Chile reverts from permanent to seasonal DST.  (Thanks to Juan
2275    Correa for the heads-up, and to Tim Parenti for corrections.)
2276    Guess that future transitions are August's and May's second
2277    Saturdays at 24:00 mainland time.  Also, call the period from
2278    2014-09-07 through 2016-05-14 daylight saving time instead of
2279    standard time, as that seems more appropriate now.
2280
2281  Changes affecting past timestamps
2282
2283    Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
2284    +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
2285    from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
2286    (Thanks to Stepan Golosunov.)
2287
2288  Changes to commentary
2289
2290    Several updates and URLs for historical and proposed Russian changes.
2291    (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
2292
2293
2294Release 2016b - 2016-03-12 17:30:14 -0800
2295
2296  Compatibility note
2297
2298    Starting with release 2016b, some data entries cause zic implementations
2299    derived from tz releases 2005j through 2015e to issue warnings like
2300    "time zone abbreviation differs from POSIX standard (+03)".
2301    These warnings should not otherwise affect zic's output and can safely be
2302    ignored on today's platforms, as the warnings refer to a restriction in
2303    POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
2304    warnings is to upgrade to zic derived from tz releases 2015f and later.
2305
2306  Changes affecting future timestamps
2307
2308    New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
2309    Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
2310    2016-03-27 at 02:00 local time.  They need distinct zones since their
2311    post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
2312    Altai Republic, Russia, which will switch from +06 to +07 on the same date
2313    and local time.  The Astrakhan change is already official; the others have
2314    passed the first reading in the State Duma and are extremely likely.
2315    Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
2316    (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
2317    and Stepan Golosunov for followup.)
2318
2319    As a trial of a new system that needs less information to be made up,
2320    the new zones use numeric time zone abbreviations like "+04"
2321    instead of invented abbreviations like "ASTT".
2322
2323    Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
2324    Steffen Thorsen.)
2325
2326    Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
2327    (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
2328    Saturday at 01:00, not March's last Friday at 24:00.
2329
2330  Changes affecting past timestamps
2331
2332    Europe/Chisinau observed DST during 1990, and switched from +04 to
2333    +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
2334    (Thanks to Stepan Golosunov.)
2335
2336    1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
2337    KUYT/KUYST.  (Thanks to Stepan Golosunov.)
2338
2339  Changes to code
2340
2341    tzselect's diagnostics and checking, and checktab.awk's checking,
2342    have been improved.  (Thanks to J William Piggott.)
2343
2344    tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
2345
2346    tzselect now tests Julian-date TZ settings more accurately.
2347    (Thanks to J William Piggott.)
2348
2349  Changes to commentary
2350
2351    Comments in zone tables have been improved.  (Thanks to J William Piggott.)
2352
2353    tzselect again limits its menu comments so that menus fit on a
2354    24×80 alphanumeric display.
2355
2356    A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
2357
2358    In the Theory file, the description of possible time zone abbreviations in
2359    tzdata has been cleaned up, as the old description was unclear and
2360    inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
2361
2362
2363Release 2016a - 2016-01-26 23:28:02 -0800
2364
2365  Changes affecting future timestamps
2366
2367    America/Cayman will not observe daylight saving this year after all.
2368    Revert our guess that it would.  (Thanks to Matt Johnson.)
2369
2370    Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
2371    (Thanks to Alexander Krivenyshev.)
2372
2373    Asia/Tehran now has DST predictions for the year 2038 and later,
2374    to be March 21 00:00 to September 21 00:00.  This is likely better
2375    than predicting no DST, albeit off by a day every now and then.
2376
2377  Changes affecting past and future timestamps
2378
2379    America/Metlakatla switched from PST all year to AKST/AKDT on
2380    2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
2381
2382    America/Santa_Isabel has been removed, and replaced with a
2383    backward compatibility link to America/Tijuana.  Its contents were
2384    apparently based on a misreading of Mexican legislation.
2385
2386  Changes affecting past timestamps
2387
2388    Asia/Karachi's two transition times in 2002 were off by a minute.
2389    (Thanks to Matt Johnson.)
2390
2391  Changes affecting build procedure
2392
2393    An installer can now combine leap seconds with use of the backzone file,
2394    e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
2395    The old 'make posix_packrat' rule is now marked as obsolescent.
2396    (Thanks to Ian Abbott for an initial implementation.)
2397
2398  Changes affecting documentation and commentary
2399
2400    A new file LICENSE makes it easier to see that the code and data
2401    are mostly public-domain.  (Thanks to James Knight.)  The three
2402    non-public-domain files now use the current (3-clause) BSD license
2403    instead of older versions of that license.
2404
2405    tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
2406    CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
2407    on editing tz source files (with a mention of Sublime zoneinfo,
2408    thanks to Gilmore Davidson).
2409
2410    The Theory and asia files now mention the 2015 book "The Global
2411    Transformation of Time, 1870-1950", and cite a couple of reviews.
2412
2413    The America/Chicago entry now documents the informal use of US
2414    central time in Fort Pierre, South Dakota.  (Thanks to Rick
2415    McDermid, Matt Johnson, and Steve Jones.)
2416
2417
2418Release 2015g - 2015-10-01 00:39:51 -0700
2419
2420  Changes affecting future timestamps
2421
2422    Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
2423    (Thanks to Fatih.)
2424
2425    Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
2426    (Thanks to Alexander Krivenyshev.)
2427
2428    Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
2429    (Thanks to Ken Rylander.)
2430
2431    Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
2432    effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
2433    New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
2434
2435  Changes affecting past timestamps
2436
2437    Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
2438
2439  Changes affecting code
2440
2441    localtime no longer mishandles America/Anchorage after 2037.
2442    (Thanks to Bradley White for reporting the bug.)
2443
2444    On hosts with signed 32-bit time_t, localtime no longer mishandles
2445    Pacific/Fiji after 2038-01-16 14:00 UTC.
2446
2447    The localtime module allows the variables 'timezone', 'daylight',
2448    and 'altzone' to be in common storage shared with other modules,
2449    and declares them in case the system <time.h> does not.
2450    (Problems reported by Kees Dekker.)
2451
2452    On platforms with tm_zone, strftime.c now assumes it is not NULL.
2453    This simplifies the code and is consistent with zdump.c.
2454    (Problem reported by Christos Zoulas.)
2455
2456  Changes affecting documentation
2457
2458   The tzfile man page now documents that transition times denote the
2459   starts (not the ends) of the corresponding time periods.
2460   (Ambiguity reported by Bill Seymour.)
2461
2462
2463Release 2015f - 2015-08-10 18:06:56 -0700
2464
2465  Changes affecting future timestamps
2466
2467    North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
2468    The abbreviation remains "KST".  (Thanks to Robert Elz.)
2469
2470    Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
2471    and Pablo Camargo.)
2472
2473  Changes affecting past and future timestamps
2474
2475    Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
2476    (Thanks to Roman Tudos.)
2477
2478  Changes affecting data format and code
2479
2480    zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
2481    field of a Rule line should now be '-'; the old values 'even',
2482    'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
2483    Although the implementation has not changed, these features do not
2484    work in the default installation, they are not used in the data,
2485    and they are now considered obsolescent.
2486
2487    zic now checks that two rules don't take effect at the same time.
2488    (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
2489    simultaneity are now documented.
2490
2491    The two characters '%z' in a zone format now stand for the UT
2492    offset, e.g., '-07' for seven hours behind UT and '+0530' for
2493    five hours and thirty minutes ahead.  This better supports time
2494    zone abbreviations conforming to POSIX.1-2001 and later.
2495
2496  Changes affecting installed data files
2497
2498    Comments for America/Halifax and America/Glace_Bay have been improved.
2499    (Thanks to Brian Inglis.)
2500
2501    Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
2502    Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
2503    installed data files for Europe/Simferopol and Europe/Tallinn.
2504    It does not affect timestamps.  (Thanks to Howard Hinnant.)
2505
2506  Changes affecting code
2507
2508    zdump and zic no longer warn about valid time zone abbreviations
2509    like '-05'.
2510
2511    Some Visual Studio 2013 warnings have been suppressed.
2512    (Thanks to Kees Dekker.)
2513
2514    'date' no longer sets the time of day and its -a, -d, -n and -t
2515    options have been removed.  Long obsolescent, the implementation
2516    of these features had porting problems.  Builders no longer need
2517    to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
2518    (Thanks to Kees Dekker for pointing out the problem.)
2519
2520  Changes affecting documentation
2521
2522    The Theory file mentions naming issues earlier, as these seem to be
2523    poorly publicized (thanks to Gilmore Davidson for reporting the problem).
2524
2525    tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
2526
2527    Mention that Herbert Samuel introduced the term "Summer Time".
2528
2529
2530Release 2015e - 2015-06-13 10:56:02 -0700
2531
2532  Changes affecting future timestamps
2533
2534    Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
2535    not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
2536
2537    Assume Cayman Islands will observe DST starting next year, using US rules.
2538    Although it isn't guaranteed, it is the most likely.
2539
2540  Changes affecting data format
2541
2542    The file 'iso3166.tab' now uses UTF-8, so that its entries can better
2543    spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
2544
2545  Changes affecting code
2546
2547    When displaying data, tzselect converts it to the current locale's
2548    encoding if the iconv command works.  (Problem reported by random832.)
2549
2550    tzselect no longer mishandles Dominica, fixing a bug introduced
2551    in Release 2014f.  (Problem reported by Owen Leibman.)
2552
2553    zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
2554    This fixes a bug introduced in Release 2014f.
2555    (Problem reported by Leonardo Chiquitto.)
2556
2557
2558Release 2015d - 2015-04-24 08:09:46 -0700
2559
2560  Changes affecting future timestamps
2561
2562    Egypt will not observe DST in 2015 and will consider canceling it
2563    permanently.  For now, assume no DST indefinitely.
2564    (Thanks to Ahmed Nazmy and Tim Parenti.)
2565
2566  Changes affecting past timestamps
2567
2568    America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
2569    1966-07-01.  Also, Yukon's time zone history is documented better.
2570    (Thanks to Brian Inglis and Dennis Ferguson.)
2571
2572  Change affecting past and future time zone abbreviations
2573
2574    The abbreviations for Hawaii-Aleutian standard and daylight times
2575    have been changed from HAST/HADT to HST/HDT, as per US Government
2576    Printing Office style.  This affects only America/Adak since 1983,
2577    as America/Honolulu was already using the new style.
2578
2579  Changes affecting code
2580
2581   zic has some minor performance improvements.
2582
2583
2584Release 2015c - 2015-04-11 08:55:55 -0700
2585
2586  Changes affecting future timestamps
2587
2588    Egypt's spring-forward transition is at 24:00 on April's last Thursday,
2589    not 00:00 on April's last Friday.  2015's transition will therefore be on
2590    Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
2591    apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
2592
2593  Changes affecting past timestamps
2594
2595    The following changes affect some pre-1991 Chile-related timestamps
2596    in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
2597
2598      The 1910 transition was January 10, not January 1.
2599
2600      The 1918 transition was September 10, not September 1.
2601
2602      The UT -04 time observed from 1932 to 1942 is now considered to
2603      be standard time, not year-round DST.
2604
2605      Santiago observed DST (UT -03) from 1946-07-15 through
2606      1946-08-31, then reverted to standard time, then switched to -05
2607      on 1947-04-01.
2608
2609      Assume transitions before 1968 were at 00:00, since we have no data
2610      saying otherwise.
2611
2612      The spring 1988 transition was 1988-10-09, not 1988-10-02.
2613      The fall 1990 transition was 1990-03-11, not 1990-03-18.
2614
2615      Assume no UT offset change for Pacific/Easter on 1890-01-01,
2616      and omit all transitions on Pacific/Easter from 1942 through 1946
2617      since we have no data suggesting that they existed.
2618
2619    One more zone has been turned into a link, as it differed
2620    from an existing zone only for older timestamps.  As usual,
2621    this change affects UT offsets in pre-1970 timestamps only.
2622    The zone's old contents have been moved to the 'backzone' file.
2623    The affected zone is America/Montreal.
2624
2625  Changes affecting commentary
2626
2627    Mention the TZUpdater tool.
2628
2629    Mention "The Time Now".  (Thanks to Brandon Ramsey.)
2630
2631
2632Release 2015b - 2015-03-19 23:28:11 -0700
2633
2634  Changes affecting future timestamps
2635
2636    Mongolia will start observing DST again this year, from the last
2637    Saturday in March at 02:00 to the last Saturday in September at 00:00.
2638    (Thanks to Ganbold Tsagaankhuu.)
2639
2640    Palestine will start DST on March 28, not March 27.  Also,
2641    correct the fall 2014 transition from September 26 to October 24.
2642    Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
2643
2644  Changes affecting past timestamps
2645
2646    The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
2647    regression.  (Thanks to Stuart Bishop for reporting the problem.)
2648
2649    Some more zones have been turned into links, when they differed
2650    from existing zones only for older timestamps.  As usual,
2651    these changes affect UT offsets in pre-1970 timestamps only.
2652    Their old contents have been moved to the 'backzone' file.
2653    The affected zones are: America/Antigua, America/Cayman,
2654    Pacific/Midway, and Pacific/Saipan.
2655
2656  Changes affecting time zone abbreviations
2657
2658    Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
2659    (Thanks to Hank W.)
2660
2661  Changes affecting code
2662
2663    Fix integer overflow bug in reference 'mktime' implementation.
2664    (Problem reported by Jörg Richter.)
2665
2666    Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
2667    to be used in the same executable as standard-library time_t functions.
2668    (Problems reported by Bradley White.)
2669
2670  Changes affecting commentary
2671
2672    Cite the recent Mexican decree changing Quintana Roo's time zone.
2673    (Thanks to Carlos Raúl Perasso.)
2674
2675    Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
2676
2677    Update info about Mars time.
2678
2679
2680Release 2015a - 2015-01-29 22:35:20 -0800
2681
2682  Changes affecting future timestamps
2683
2684    The Mexican state of Quintana Roo, represented by America/Cancun,
2685    will shift from Central Time with DST to Eastern Time without DST
2686    on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
2687
2688    Chile will not change clocks in April or thereafter; its new standard time
2689    will be its old daylight saving time.  This affects America/Santiago,
2690    Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
2691
2692    New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
2693    (Thanks to Tim Parenti.)
2694
2695  Changes affecting past timestamps
2696
2697    Iceland observed DST in 1919 and 1921, and its 1939 fallback
2698    transition was Oct. 29, not Nov. 29.  Remove incorrect data from
2699    Shanks about time in Iceland between 1837 and 1908.
2700
2701    Some more zones have been turned into links, when they differed
2702    from existing zones only for older timestamps.  As usual,
2703    these changes affect UT offsets in pre-1970 timestamps only.
2704    Their old contents have been moved to the 'backzone' file.
2705    The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
2706    and Asia/Muscat.
2707
2708  Changes affecting code
2709
2710    tzalloc now scrubs time zone abbreviations compatibly with the way
2711    that tzset always has, by replacing invalid bytes with '_' and by
2712    shortening too-long abbreviations.
2713
2714    tzselect ports to POSIX awk implementations, no longer mishandles
2715    POSIX TZ settings when GNU awk is used, and reports POSIX TZ
2716    settings to the user.  (Thanks to Stefan Kuhn.)
2717
2718  Changes affecting build procedure
2719
2720    'make check' now checks for links to links in the data.
2721    One such link (for Africa/Asmera) has been fixed.
2722    (Thanks to Stephen Colebourne for pointing out the problem.)
2723
2724  Changes affecting commentary
2725
2726    The leapseconds file commentary now mentions the expiration date.
2727    (Problem reported by Martin Burnicki.)
2728
2729    Update Mexican Library of Congress URL.
2730
2731
2732Release 2014j - 2014-11-10 17:37:11 -0800
2733
2734  Changes affecting current and future timestamps
2735
2736    Turks & Caicos' switch from US eastern time to UT -04 year-round
2737    did not occur on 2014-11-02 at 02:00.  It's currently scheduled
2738    for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
2739
2740  Changes affecting past timestamps
2741
2742    Many pre-1989 timestamps have been corrected for Asia/Seoul and
2743    Asia/Pyongyang, based on sources for the Korean-language Wikipedia
2744    entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
2745    longer guess that Pyongyang mimicked Seoul time after World War II,
2746    as this is politically implausible.
2747
2748    Some more zones have been turned into links, when they differed
2749    from existing zones only for older timestamps.  As usual,
2750    these changes affect UT offsets in pre-1970 timestamps only.
2751    Their old contents have been moved to the 'backzone' file.
2752    The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
2753    Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
2754    Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
2755    Indian/Mayotte.
2756
2757  Changes affecting commentary
2758
2759    The commentary is less enthusiastic about Shanks as a source,
2760    and is more careful to distinguish UT from UTC.
2761
2762
2763Release 2014i - 2014-10-21 22:04:57 -0700
2764
2765  Changes affecting future timestamps
2766
2767    Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
2768    (Thanks to Ken Rylander for the heads-up.)  Guess that future
2769    years will use a similar pattern.
2770
2771    A new Zone Pacific/Bougainville, for the part of Papua New Guinea
2772    that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
2773    (Thanks to Kiley Walbom for the heads-up.)
2774
2775  Changes affecting time zone abbreviations
2776
2777    Since Belarus is not changing its clocks even though Moscow is,
2778    the time zone abbreviation in Europe/Minsk is changing from FET
2779    to its more-traditional value MSK on 2014-10-26 at 01:00.
2780    (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
2781
2782    The new abbreviation IDT stands for the pre-1976 use of UT +08 in
2783    Indochina, to distinguish it better from ICT (+07).
2784
2785  Changes affecting past timestamps
2786
2787    Many timestamps have been corrected for Asia/Ho_Chi_Minh before 1976
2788    (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
2789    authoritative book).  Asia/Ho_Chi_Minh has been added to
2790    zone1970.tab, to give tzselect users in Vietnam two choices,
2791    since north and south Vietnam disagreed after our 1970 cutoff.
2792
2793    Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
2794    they differed from existing zones only for older timestamps.  As
2795    usual, these changes affect pre-1970 timestamps only.  Their old
2796    contents have been moved to the 'backzone' file.
2797
2798  Changes affecting code
2799
2800    The time-related library functions now set errno on failure, and
2801    some crashes in the new tzalloc-related library functions have
2802    been fixed.  (Thanks to Christos Zoulas for reporting most of
2803    these problems and for suggesting fixes.)
2804
2805    If USG_COMPAT is defined and the requested timestamp is standard time,
2806    the tz library's localtime and mktime functions now set the extern
2807    variable timezone to a value appropriate for that timestamp; and
2808    similarly for ALTZONE, daylight saving time, and the altzone variable.
2809    This change is a companion to the tzname change in 2014h, and is
2810    designed to make timezone and altzone more compatible with tzname.
2811
2812    The tz library's functions now set errno to EOVERFLOW if they fail
2813    because the result cannot be represented.  ctime and ctime_r now
2814    return NULL and set errno when a timestamp is out of range, rather
2815    than having undefined behavior.
2816
2817    Some bugs associated with the new 2014g functions have been fixed.
2818    This includes a bug that largely incapacitated the new functions
2819    time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
2820    It also includes some uses of uninitialized variables after tzalloc.
2821    The new code uses the standard type 'ssize_t', which the Makefile
2822    now gives porting advice about.
2823
2824  Changes affecting commentary
2825
2826    Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
2827
2828
2829Release 2014h - 2014-09-25 18:59:03 -0700
2830
2831  Changes affecting past timestamps
2832
2833    America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
2834
2835    Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
2836    not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
2837
2838    Some more zones have been turned into links, when they differed
2839    from existing zones only for older timestamps.  As usual,
2840    these changes affect UT offsets in pre-1970 timestamps only.
2841    Their old contents have been moved to the 'backzone' file.
2842    The affected zones are: Africa/Blantyre, Africa/Bujumbura,
2843    Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
2844    Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
2845
2846  Changes affecting code
2847
2848    zdump -V and -v now output gmtoff= values on all platforms,
2849    not merely on platforms defining TM_GMTOFF.
2850
2851    The tz library's localtime and mktime functions now set tzname to a value
2852    appropriate for the requested timestamp, and zdump now uses this
2853    on platforms not defining TM_ZONE, fixing a 2014g regression.
2854    (Thanks to Tim Parenti for reporting the problem.)
2855
2856    The tz library no longer sets tzname if localtime or mktime fails.
2857
2858    zdump -c no longer mishandles transitions near year boundaries.
2859    (Thanks to Tim Parenti for reporting the problem.)
2860
2861    An access to uninitialized data has been fixed.
2862    (Thanks to Jörg Richter for reporting the problem.)
2863
2864    When THREAD_SAFE is defined, the code ports to the C11 memory model.
2865    A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
2866    and two threads race to initialize data used by gmtime-like functions.
2867    (Thanks to Andy Heninger for reporting the problems.)
2868
2869  Changes affecting build procedure
2870
2871    'make check' now checks better for properly-sorted data.
2872
2873  Changes affecting documentation and commentary
2874
2875    zdump's gmtoff=N output is now documented, and its isdst=D output
2876    is now documented to possibly output D values other than 0 or 1.
2877
2878    zdump -c's treatment of years is now documented to use the
2879    Gregorian calendar and Universal Time without leap seconds,
2880    and its behavior at cutoff boundaries is now documented better.
2881    (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
2882
2883    Programs are now documented to use the proleptic Gregorian calendar.
2884    (Thanks to Alan Barrett for the suggestion.)
2885
2886    Fractional-second GMT offsets have been documented for civil time
2887    in 19th-century Chennai, Jakarta, and New York.
2888
2889
2890Release 2014g - 2014-08-28 12:31:23 -0700
2891
2892  Changes affecting future timestamps
2893
2894    Turks & Caicos is switching from US eastern time to UT -04
2895    year-round, modeled as a switch on 2014-11-02 at 02:00.
2896    [As noted in 2014j, this switch was later delayed.]
2897
2898  Changes affecting past timestamps
2899
2900    Time in Russia or the USSR before 1926 or so has been corrected by
2901    a few seconds in the following zones: Asia/Irkutsk,
2902    Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
2903    Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
2904    Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
2905    Vladimir Karpinsky.)
2906
2907    The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
2908    This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
2909    Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
2910    GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
2911    (Thanks to Stephen Colebourne for pointing to the decree.)
2912
2913    Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
2914
2915    A new file 'backzone' contains data which may appeal to
2916    connoisseurs of old timestamps, although it is out of scope for
2917    the tz database, is often poorly sourced, and contains some data
2918    that is known to be incorrect.  The new file is not recommended
2919    for ordinary use and its entries are not installed by default.
2920    (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
2921    Isle of Man entries.)
2922
2923    Some more zones have been turned into links, when they differed
2924    from existing zones only for older timestamps.  As usual,
2925    these changes affect UT offsets in pre-1970 timestamps only.
2926    Their old contents have been moved to the 'backzone' file.
2927    The affected zones are: Africa/Bangui, Africa/Brazzaville,
2928    Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
2929    Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
2930
2931  Changes affecting code
2932
2933    Unless NETBSD_INSPIRED is defined to 0, the tz library now
2934    supplies functions for creating and using objects that represent
2935    timezones. The new functions are tzalloc, tzfree, localtime_rz,
2936    mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
2937    time2posix_z.  They are intended for performance: for example,
2938    localtime_rz (unlike localtime_r) is trivially thread-safe without
2939    locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
2940    functions, and to Alan Barrett and Jonathan Lennox for helping to
2941    debug the change.)
2942
2943    zdump now builds with the tz library unless USE_LTZ is defined to 0,
2944    This lets zdump use tz features even if the system library lacks them.
2945    To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
2946    TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
2947
2948    zdump now uses localtime_rz if available, as it's significantly faster,
2949    and it can help zdump better diagnose invalid timezone names.
2950    Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
2951    defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
2952    not available, zdump now uses localtime_r and tzset if available,
2953    as this is a bit cleaner and faster than plain localtime.  Compile
2954    with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
2955    lacks these two functions.
2956
2957    If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
2958    Although not needed for tz's own applications, which are single-threaded,
2959    this supports POSIX better if the tz library is used in multithreaded apps.
2960
2961    Some crashes have been fixed when zdump or the tz library is given
2962    invalid or outlandish input.
2963
2964    The tz library no longer mishandles leap seconds on platforms with
2965    unsigned time_t in timezones that lack ordinary transitions after 1970.
2966
2967    The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
2968    already defined, to make it easier to configure on common platforms.
2969    Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
2970
2971    Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
2972    assumes that reading uninitialized memory yields garbage values
2973    but does not cause other problems such as traps.
2974
2975    If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
2976    more likely to guess right for ambiguous timestamps near
2977    transitions where tm_isdst does not change.
2978
2979    If HAVE_STRFTIME_L is defined to 1, the tz library now defines
2980    strftime_l for compatibility with recent versions of POSIX.
2981    Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
2982    to 1 on recent POSIX versions, and to 0 otherwise.
2983
2984    tzselect -c now uses a hybrid distance measure that works better
2985    in Africa.  (Thanks to Alan Barrett for noting the problem.)
2986
2987    The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
2988    or when time_tz is defined.
2989
2990    When HAVE_UTMPX_H is set the 'date' command now builds on systems
2991    whose <utmpx.h> file does not define WTMPX_FILE, and when setting
2992    the date it updates the wtmpx file if _PATH_WTMPX is defined.
2993    This affects GNU/Linux and similar systems.
2994
2995    For easier maintenance later, some C code has been simplified,
2996    some lint has been removed, and the code has been tweaked so that
2997    plain 'make' is more likely to work.
2998
2999    The C type 'bool' is now used for boolean values, instead of 'int'.
3000
3001    The long-obsolete LOCALE_HOME code has been removed.
3002
3003    The long-obsolete 'gtime' function has been removed.
3004
3005  Changes affecting build procedure
3006
3007    'zdump' no longer links in ialloc.o, as it's not needed.
3008
3009    'make check_time_t_alternatives' no longer assumes GNU diff.
3010
3011  Changes affecting distribution tarballs
3012
3013    The files checktab.awk and zoneinfo2tdf.pl are now distributed in
3014    the tzdata tarball instead of the tzcode tarball, since they help
3015    maintain the data.  The NEWS and Theory files are now also
3016    distributed in the tzdata tarball, as they're relevant for data.
3017    (Thanks to Alan Barrett for pointing this out.)  Also, the
3018    leapseconds.awk file is no longer distributed in the tzcode
3019    tarball, since it belongs in the tzdata tarball (where 2014f
3020    inadvertently also distributed it).
3021
3022  Changes affecting documentation and commentary
3023
3024    A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
3025    suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
3026    for debugging it.)
3027
3028    The man pages have been updated to use function prototypes,
3029    to document thread-safe variants like localtime_r, and to document
3030    the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
3031    mktime_z.
3032
3033    The fields in Link lines have been renamed to be more descriptive
3034    and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
3035    and LINK-TO has become LINK-NAME.
3036
3037    tz-link.htm mentions the IETF's tzdist working group; Windows
3038    Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
3039
3040    Some broken URLs have been fixed in the commentary.  (Thanks to
3041    Lester Caine.)
3042
3043    Commentary about Philippines DST has been updated, and commentary
3044    on pre-1970 time in India has been added.
3045
3046
3047Release 2014f - 2014-08-05 17:42:36 -0700
3048
3049  Changes affecting future timestamps
3050
3051    Russia will subtract an hour from most of its time zones on 2014-10-26
3052    at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
3053    There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
3054    Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
3055    (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
3056    (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
3057    (Europe/Samara) are not changing their clocks.  The changed zones are
3058    Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
3059    Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
3060    Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
3061    Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
3062    subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
3063    but not its UTC offset.  Two zones are added: Asia/Chita (split
3064    from Asia/Yakutsk, and also with two hours subtracted) and
3065    Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
3066    subtracted).  (Thanks to Tim Parenti for much of the above.)
3067
3068  Changes affecting time zone abbreviations
3069
3070    Australian eastern time zone abbreviations are now AEST/AEDT not EST,
3071    and similarly for the other Australian zones.  That is, for eastern
3072    standard and daylight saving time the abbreviations are AEST and AEDT
3073    instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
3074    and AWST/AWDT are now used instead of the former CST, CWST, and WST.
3075    This change does not affect UT offsets, only time zone abbreviations.
3076    (Thanks to Rich Tibbett and many others.)
3077
3078    Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
3079    effective 2014-10-26 at 02:00 local time.
3080
3081    The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
3082    has been changed from URUT to XJT.  (Thanks to Luther Ma.)
3083
3084    Prefer MSK/MSD for Moscow time in Russia, even in other cities.
3085    Similarly, prefer EET/EEST for eastern European time in Russia.
3086
3087    Change time zone abbreviations in (western) Samoa to use "ST" and
3088    "DT" suffixes, as this is more likely to match common practice.
3089    Prefix "W" to (western) Samoa time when its standard-time offset
3090    disagrees with that of American Samoa.
3091
3092    America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
3093
3094    Time zone abbreviations have been updated for Japan's two time
3095    zones used 1896-1937.  JWST now stands for Western Standard
3096    Time, and JCST for Central Standard Time (formerly this was CJT).
3097    These abbreviations are now used for time in Korea, Taiwan,
3098    and Sakhalin while controlled by Japan.
3099
3100  Changes affecting past timestamps
3101
3102    China's five zones have been simplified to two, since the post-1970
3103    differences in the other three seem to have been imaginary.  The
3104    zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
3105    removed; backwards-compatibility links still work, albeit with
3106    different behaviors for timestamps before May 1980.  Asia/Urumqi's
3107    1980 transition to UT +08 has been removed, so that it is now at
3108    +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
3109    Treindl sent helpful translations of two papers by Guo Qingsheng.)
3110
3111    Some zones have been turned into links, when they differed from existing
3112    zones only for older UT offsets where data entries were likely invented.
3113    These changes affect UT offsets in pre-1970 timestamps only.  This is
3114    similar to the change in release 2013e, except this time for western
3115    Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
3116    Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
3117    Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
3118    Atlantic/St_Helena.  This also affects the backwards-compatibility
3119    link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
3120    Tim Parenti, and David Patte for reporting problems in earlier
3121    versions of this change.)
3122
3123    Asia/Shanghai's pre-standard-time UT offset has been changed from
3124    8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
3125    transition to standard time has been changed from 1928 to 1901.
3126
3127    Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
3128    then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
3129    In 1946 it observed DST from 05-15 through 09-30; in 1947
3130    from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
3131    (Thanks to Yu-Cheng Chuang.)
3132
3133    Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
3134
3135    Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
3136    10-03 at 00:00.  (Thanks to Konstantin Hyppönen.)
3137
3138    Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
3139    period from 1911 to 1950.
3140
3141    Pacific/Chatham has been changed to New Zealand standard time plus
3142    45 minutes for the period before 1957, reflecting a 1956 remark in
3143    the New Zealand parliament.
3144
3145    Europe/Budapest has several pre-1946 corrections: in 1918 the transition
3146    out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
3147    1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
3148    not 04-06 at 02:00; and there was no DST in 1920.
3149
3150    Africa/Accra is now assumed to have observed DST from 1920 through 1935.
3151
3152    Time in Russia before 1927 or so has been corrected by a few seconds in
3153    the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
3154    Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
3155    Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
3156    point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
3157
3158  Changes affecting data format
3159
3160    A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
3161    The new file's extended format allows multiple country codes per zone.
3162    The older file is still installed but is deprecated; its format is
3163    not changing and it will still be distributed for a while, but new
3164    applications should use the new file.
3165
3166    The new file format simplifies maintenance of obscure locations.
3167    To test this, it adds coverage for the Crozet Islands and the
3168    Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
3169
3170    The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
3171    It is still ASCII now, but commentary about the switch has been added.
3172    The new file 'zone1970.tab' already uses UTF-8.
3173
3174  Changes affecting code
3175
3176    'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
3177    is defined.  (Thanks to Elliott Hughes for reporting the problem.)
3178
3179    'zic' no longer mishandles input when ignoring case in locales that
3180    are not compatible with English, e.g., unibyte Turkish locales when
3181    compiled with HAVE_GETTEXT.
3182
3183    Error diagnostics of 'zic' and 'yearistype' have been reworded so that
3184    they no longer use ASCII '-' as if it were a dash.
3185
3186    'zic' now rejects output file names that contain '.' or '..' components.
3187    (Thanks to Tim Parenti for reporting the problem.)
3188
3189    'zic -v' now warns about output file names that do not follow
3190    POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
3191    David Olson for starting the ball rolling on this.)
3192
3193    Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
3194
3195  Changes affecting build procedure
3196
3197    'zic' no longer links in localtime.o and asctime.o, as they're not needed.
3198    (Thanks to John Cochran.)
3199
3200  Changes affecting documentation and commentary
3201
3202    The 'Theory' file documents legacy names, the longstanding
3203    exceptions to the POSIX-inspired file name rules.
3204
3205    The 'zic' documentation clarifies the role of time types when
3206    interpreting dates.  (Thanks to Arthur David Olson.)
3207
3208    Documentation and commentary now prefer UTF-8 to US-ASCII,
3209    allowing the use of proper accents in foreign words and names.
3210    Code and data have not changed because of this.  (Thanks to
3211    Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
3212    this.)
3213
3214    Non-HTML documentation and commentary now use plain-text URLs instead of
3215    HTML insertions, and are more consistent about bracketing URLs when they
3216    are not already surrounded by white space.  (Thanks to suggestions by
3217    Steffen Nurpmeso.)
3218
3219    There is new commentary about Xujiahui Observatory, the five time-zone
3220    project in China from 1918 to 1949, timekeeping in Japanese-occupied
3221    Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
3222    warlord Jin Shuren in the data.
3223
3224    Commentary about the coverage of each Russian zone has been standardized.
3225    (Thanks to Tim Parenti.)
3226
3227    There is new commentary about contemporary timekeeping in Ethiopia.
3228
3229    Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
3230
3231    There is new commentary about time in Poland in 1919.
3232
3233    Proper credit has been given to DST inventor George Vernon Hudson.
3234
3235    Commentary about time in Metlakatla, AK and Resolute, NU has been
3236    improved, with a new source for the former.
3237
3238    In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
3239    is uninhabited.
3240
3241    Commentary about permanent Antarctic bases has been updated.
3242
3243    Several typos have been corrected.  (Thanks to Tim Parenti for
3244    contributing some of these fixes.)
3245
3246    tz-link.htm now mentions the JavaScript libraries Moment Timezone,
3247    TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
3248    from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
3249    (Thanks to a heads-up from Dirkjan Ochtman.)
3250
3251    The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
3252    have been removed.  These obsolescent US Naval Observatory entries were no
3253    longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
3254
3255
3256Release 2014e - 2014-06-12 21:53:52 -0700
3257
3258  Changes affecting near-future timestamps
3259
3260    Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
3261    (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
3262    switch to standard time at 24:00 the last Thursday before Ramadan, and
3263    back to DST at 00:00 the first Friday after Ramadan.
3264
3265    Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
3266    to Milamber Space Network.)  Guess that from 2015 on Morocco will
3267    temporarily switch to standard time at 03:00 the last Saturday before
3268    Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
3269
3270  Changes affecting past timestamps
3271
3272    The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
3273    "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
3274    "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
3275    in 1991.  (Thanks to Hank W. for reporting the problems.)
3276
3277  Changes affecting commentary
3278
3279    tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
3280    draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
3281    removes stale pointers to World Time Explorer and WORLDTIME.
3282
3283
3284Release 2014d - 2014-05-27 21:34:40 -0700
3285
3286  Changes affecting code
3287
3288    zic no longer generates files containing timestamps before the Big Bang.
3289    This works around GNOME glib bug 878
3290    <https://gitlab.gnome.org/GNOME/glib/issues/878>
3291    (Thanks to Leonardo Chiquitto for reporting the bug, and to
3292    Arthur David Olson and James Cloos for suggesting improvements to the fix.)
3293
3294  Changes affecting documentation
3295
3296    tz-link.htm now mentions GNOME.
3297
3298
3299Release 2014c - 2014-05-13 07:44:13 -0700
3300
3301  Changes affecting near-future timestamps
3302
3303    Egypt observes DST starting 2014-05-15 at 24:00.
3304    (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
3305    Details have not been announced, except that DST will not be observed
3306    during Ramadan.  Guess that DST will stop during the same Ramadan dates as
3307    Morocco, and that Egypt's future spring and fall transitions will be the
3308    same as 2010 when it last observed DST, namely April's last Friday at
3309    00:00 to September's last Thursday at 23:00 standard time.  Also, guess
3310    that Ramadan transitions will be at 00:00 standard time.
3311
3312  Changes affecting code
3313
3314    zic now generates transitions for minimum time values, eliminating guesswork
3315    when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
3316
3317    Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
3318
3319  Changes affecting commentary and documentation
3320
3321    Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
3322
3323
3324Release 2014b - 2014-03-24 21:28:50 -0700
3325
3326  Changes affecting near-future timestamps
3327
3328    Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
3329    (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
3330
3331    New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
3332    Bengt-Inge Larsson.)  This is currently an approximation; a better version
3333    will require the zic and localtime fixes mentioned below, and the plan is
3334    to wait for a while until at least the zic fixes propagate.
3335
3336  Changes affecting code
3337
3338    'zic' and 'localtime' no longer reject locations needing four transitions
3339    per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
3340    Also, 'zic' avoids some unlikely failures due to integer overflow.
3341
3342  Changes affecting build procedure
3343
3344    'make check' now detects Rule lines defined but never used.
3345    The NZAQ rules, an instance of this problem, have been removed.
3346
3347  Changes affecting commentary and documentation
3348
3349    Fix Tuesday/Thursday typo in description of time in Israel.
3350    (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
3351
3352    Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
3353    to Donald MacQueen.)  Instead, the Microsoft Windows Store app
3354    library supports them.
3355
3356    Add comments about Johnston Island time in the 1960s.
3357    (Thanks to Lyle McElhaney.)
3358
3359    Morocco's 2014 DST start will be as predicted.
3360    (Thanks to Sebastien Willemijns.)
3361
3362
3363Release 2014a - 2014-03-07 23:30:29 -0800
3364
3365  Changes affecting near-future timestamps
3366
3367    Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
3368    the heads-up, and to Tim Parenti for simplifying the update.)
3369
3370  Changes affecting past timestamps
3371
3372    Fiji ended DST on 2014-01-19 at 02:00, not the previously-scheduled 03:00.
3373    (Thanks to Steffen Thorsen.)
3374
3375    Ukraine switched from Moscow to Eastern European time on 1990-07-01
3376    (not 1992-01-01), and observed DST during the entire next winter.
3377    (Thanks to Vladimir in Moscow via Alois Treindl.)
3378
3379    In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
3380    (Thanks to Avigdor Finkelstein.)
3381
3382  Changes affecting code
3383
3384    A uninitialized-storage bug in 'localtime' has been fixed.
3385    (Thanks to Logan Chien.)
3386
3387  Changes affecting the build procedure
3388
3389    The settings for 'make check_web' now default to Ubuntu 13.10.
3390
3391  Changes affecting commentary and documentation
3392
3393    The boundary of the US Pacific time zone is given more accurately.
3394    (Thanks to Alan Mintz.)
3395
3396    Chile's 2014 DST will be as predicted.  (Thanks to José Miguel Garrido.)
3397
3398    Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raúl Perasso.)
3399
3400    Better descriptions of countries with same time zone history as
3401    Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
3402
3403    Several changes affect tz-link.htm, the main web page.
3404
3405      Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
3406      David Braverman).
3407
3408      Mention xCal (Internet RFC 6321) and jCal.
3409
3410      Microsoft has some support for tz database names.
3411
3412      CLDR data formats include both XML and JSON.
3413
3414      Mention Maggiolo's map of solar vs standard time.
3415      (Thanks to Arthur David Olson.)
3416
3417      Mention TZ4Net.  (Thanks to Matt Johnson.)
3418
3419      Mention the timezone-olson Haskell package.
3420
3421      Mention zeitverschiebung.net.  (Thanks to Martin Jäger.)
3422
3423      Remove moribund links to daylight-savings-time.info and to
3424      Simple Timer + Clocks.
3425
3426      Update two links.  (Thanks to Oscar van Vlijmen.)
3427
3428      Fix some formatting glitches, e.g., remove random newlines from
3429      abbr elements' title attributes.
3430
3431
3432Release 2013i - 2013-12-17 07:25:23 -0800
3433
3434  Changes affecting near-future timestamps:
3435
3436    Jordan switches back to standard time at 00:00 on December 20, 2013.
3437    The 2006-2011 transition schedule is planned to resume in 2014.
3438    (Thanks to Steffen Thorsen.)
3439
3440  Changes affecting past timestamps:
3441
3442    In 2004, Cuba began DST on March 28, not April 4.
3443    (Thanks to Steffen Thorsen.)
3444
3445  Changes affecting code
3446
3447    The compile-time flag NOSOLAR has been removed, as nowadays the
3448    benefit of slightly shrinking runtime table size is outweighed by the
3449    cost of disallowing potential future updates that exceed old limits.
3450
3451  Changes affecting documentation and commentary
3452
3453    The files solar87, solar88, and solar89 are no longer distributed.
3454    They were a negative experiment - that is, a demonstration that
3455    tz data can represent solar time only with some difficulty and error.
3456    Their presence in the distribution caused confusion, as Riyadh
3457    civil time was generally not solar time in those years.
3458
3459    tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
3460
3461
3462Release 2013h - 2013-10-25 15:32:32 -0700
3463
3464  Changes affecting current and future timestamps:
3465
3466    Libya has switched its UT offset back to +02 without DST, instead
3467    of +01 with DST.  (Thanks to Even Scharning.)
3468
3469    Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
3470    (Thanks to Gwillim Law.)
3471
3472  Changes affecting future timestamps:
3473
3474    Acre and (we guess) western Amazonas will switch from UT -04 to -05
3475    on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
3476    (Thanks to Steffen Thorsen.)
3477
3478    Add entries for DST transitions in Morocco in the year 2038.
3479    This avoids some year-2038 glitches introduced in 2013g.
3480    (Thanks to Yoshito Umaoka for reporting the problem.)
3481
3482  Changes affecting API
3483
3484    The 'tzselect' command no longer requires the 'select' command,
3485    and should now work with /bin/sh on more platforms.  It also works
3486    around a bug in BusyBox awk before version 1.21.0.  (Thanks to
3487    Patrick 'P. J.' McDermott and Alan Barrett.)
3488
3489  Changes affecting code
3490
3491    Fix localtime overflow bugs with 32-bit unsigned time_t.
3492
3493    zdump no longer assumes sscanf returns maximal values on overflow.
3494
3495  Changes affecting the build procedure
3496
3497    The builder can specify which programs to use, if any, instead of
3498    'ar' and 'ranlib', and libtz.a is now built locally before being
3499    installed.  (Thanks to Michael Forney.)
3500
3501    A dependency typo in the 'zdump' rule has been fixed.
3502    (Thanks to Andrew Paprocki.)
3503
3504    The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
3505    work as specified by POSIX.2-1992 or later; this is portable nowadays.
3506
3507    'make clean' no longer removes 'leapseconds', since it's
3508    host-independent and is part of the distribution.
3509
3510    The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
3511
3512  Changes affecting documentation and commentary
3513
3514    tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
3515    (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
3516
3517    Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
3518    8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
3519    longer maintained) and for old advisories.  SOFA now does C.
3520
3521Release 2013g - 2013-09-30 21:08:26 -0700
3522
3523  Changes affecting current and near-future timestamps
3524
3525    Morocco now observes DST from the last Sunday in March to the last
3526    Sunday in October, not April to September respectively.  (Thanks
3527    to Steffen Thorsen.)
3528
3529  Changes affecting 'zic'
3530
3531    'zic' now runs on platforms that lack both hard links and symlinks.
3532    (Thanks to Theo Veenker for reporting the problem, for MinGW.)
3533    Also, fix some bugs on platforms that lack hard links but have symlinks.
3534
3535    'zic -v' again warns that Asia/Tehran has no POSIX environment variable
3536    to predict the far future, fixing a bug introduced in 2013e.
3537
3538  Changes affecting the build procedure
3539
3540    The 'leapseconds' file is again put into the tzdata tarball.
3541    Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
3542    Matt Burgess and Ian Abbott.)  The timestamps of these and other
3543    dependent files in tarballs are adjusted more consistently.
3544
3545  Changes affecting documentation and commentary
3546
3547    The README file is now part of the data tarball as well as the code.
3548    It now states that files are public domain unless otherwise specified.
3549    (Thanks to Andrew Main (Zefram) for asking for clarifications.)
3550    Its details about the 1989 release moved to a place of honor near
3551    the end of NEWS.
3552
3553
3554Release 2013f - 2013-09-24 23:37:36 -0700
3555
3556  Changes affecting near-future timestamps
3557
3558    Tocantins will very likely not observe DST starting this spring.
3559    (Thanks to Steffen Thorsen.)
3560
3561    Jordan will likely stay at UT +03 indefinitely, and will not fall
3562    back this fall.
3563
3564    Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
3565
3566  Changes affecting API
3567
3568    The types of the global variables 'timezone' and 'altzone' (if present)
3569    have been changed back to 'long'.  This is required for 'timezone'
3570    by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
3571    These variables were originally 'long' in the tz code, but were
3572    mistakenly changed to 'time_t' in 1987; nobody reported the
3573    incompatibility until now.  The difference matters on x32, where
3574    'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
3575
3576  Changes affecting the build procedure
3577
3578    Avoid long strings in leapseconds.awk to work around a mawk bug.
3579    (Thanks to Cyril Baurand.)
3580
3581  Changes affecting documentation and commentary
3582
3583    New file 'NEWS' that contains release notes like this one.
3584
3585    Paraguay's law does not specify DST transition time; 00:00 is customary.
3586    (Thanks to Waldemar Villamayor-Venialbo.)
3587
3588    Minor capitalization fixes.
3589
3590  Changes affecting version-control only
3591
3592    The experimental GitHub repository now contains annotated and
3593    signed tags for recent releases, e.g., '2013e' for Release 2013e.
3594    Releases are tagged starting with 2012e; earlier releases were
3595    done differently, and tags would either not have a simple name or
3596    not exactly match what was released.
3597
3598    'make set-timestamps' is now simpler and a bit more portable.
3599
3600
3601Release 2013e - 2013-09-19 23:50:04 -0700
3602
3603  Changes affecting near-future timestamps
3604
3605    This year Fiji will start DST on October 27, not October 20.
3606    (Thanks to David Wheeler for the heads-up.)  For now, guess that
3607    Fiji will continue to spring forward the Sunday before the fourth
3608    Monday in October.
3609
3610  Changes affecting current and future time zone abbreviations
3611
3612    Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
3613    time zone abbreviations since 1932.  (Thanks to George Ziegler,
3614    Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
3615    Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
3616    Asia/Makassar, and Asia/Pontianak.
3617
3618    Use ART (UT -03, standard time), rather than WARST (also -03, but
3619    daylight saving time) for San Luis, Argentina since 2009.
3620
3621  Changes affecting Godthåb timestamps after 2037 if version mismatch
3622
3623    Allow POSIX-like TZ strings where the transition time's hour can
3624    range from -167 through 167, instead of the POSIX-required 0
3625    through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
3626    new Fiji rules.  This is a more-compact way to represent
3627    far-future timestamps for America/Godthab, America/Santiago,
3628    Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
3629    Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
3630    this change.  (Derived from a suggestion by Arthur David Olson.)
3631
3632    Allow POSIX-like TZ strings where daylight saving time is in
3633    effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
3634    Argentina Summer Time all year.  This supports a more-compact way
3635    to represent the 2013d data for America/Argentina/San_Luis.
3636    Because of the change for San Luis noted above this change does not
3637    affect the current data.  (Thanks to Andrew Main (Zefram) for
3638    suggestions that improved this change.)
3639
3640    Where these two TZ changes take effect, there is a minor extension
3641    to the tz file format in that it allows new values for the
3642    embedded TZ-format string, and the tz file format version number
3643    has therefore been increased from 2 to 3 as a precaution.
3644    Version-2-based client code should continue to work as before for
3645    all timestamps before 2038.  Existing version-2-based client code
3646    (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
3647    files, and typically works in practice even for timestamps after
3648    2037; the only known exception is America/Godthab.
3649
3650  Changes affecting timestamps before 1970
3651
3652    Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
3653    some errors before 1947.
3654
3655    Some zones have been turned into links, when they differ from existing
3656    zones only in older data entries that were likely invented or that
3657    differ only in LMT or transitions from LMT.  These changes affect
3658    only timestamps before 1943.  The affected zones are:
3659    Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
3660    America/Grenada, America/Guadeloupe, America/Marigot,
3661    America/Montserrat, America/St_Barthelemy, America/St_Kitts,
3662    America/St_Lucia, America/St_Thomas, America/St_Vincent,
3663    America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
3664    confirming that the old Europe/Vaduz zone was wrong and the new
3665    link is better for WWII-era times.)
3666
3667    Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
3668    America/Cayman, America/Jamaica and America/Grand_Turk timestamps
3669    from 1890 to 1912.
3670
3671    Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
3672    This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
3673    to Alois Treindl.)
3674
3675    Change the date of the circa-1850 Zurich transition from 1849-09-12
3676    to 1853-07-16, overriding Shanks with data from Messerli about
3677    postal and telegraph time in Switzerland.
3678
3679  Changes affecting time zone abbreviations before 1970
3680
3681    For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
3682    as Jakarta was called Batavia back then.
3683
3684  Changes affecting API
3685
3686    The 'zic' command now outputs a dummy transition when far-future
3687    data can't be summarized using a TZ string, and uses a 402-year
3688    window rather than a 400-year window.  For the current data, this
3689    affects only the Asia/Tehran file.  It does not affect any of the
3690    timestamps that this file represents, so zdump outputs the same
3691    information as before.  (Thanks to Andrew Main (Zefram).)
3692
3693    The 'date' command has a new '-r' option, which lets you specify
3694    the integer time to display, a la FreeBSD.
3695
3696    The 'tzselect' command has two new options '-c' and '-n', which lets you
3697    select a zone based on latitude and longitude.
3698
3699    The 'zic' command's '-v' option now warns about constructs that
3700    require the new version-3 binary file format.  (Thanks to Arthur
3701    David Olson for the suggestion.)
3702
3703    Support for floating-point time_t has been removed.
3704    It was always dicey, and POSIX no longer requires it.
3705    (Thanks to Eric Blake for suggesting to the POSIX committee to
3706    remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
3707    Heninger, Arthur David Olson, and Alois Treindl, for reporting
3708    bugs and elucidating some of the corners of the old floating-point
3709    implementation.)
3710
3711    The signatures of 'offtime', 'timeoff', and 'gtime' have been
3712    changed back to the old practice of using 'long' to represent UT
3713    offsets.  This had been inadvertently and mistakenly changed to
3714    'int_fast32_t'.  (Thanks to Christos Zoulas.)
3715
3716    The code avoids undefined behavior on integer overflow in some
3717    more places, including gmtime, localtime, mktime and zdump.
3718
3719  Changes affecting the zdump utility
3720
3721    zdump now outputs "UT" when referring to Universal Time, not "UTC".
3722    "UTC" does not make sense for timestamps that predate the introduction
3723    of UTC, whereas "UT", a more-generic term, does.  (Thanks to Steve Allen
3724    for clarifying UT vs UTC.)
3725
3726  Data changes affecting behavior of tzselect and similar programs
3727
3728    Country code BQ is now called the more-common name "Caribbean Netherlands"
3729    rather than the more-official "Bonaire, St Eustatius & Saba".
3730
3731    Remove from zone.tab the names America/Montreal, America/Shiprock,
3732    and Antarctica/South_Pole, as they are equivalent to existing
3733    same-country-code zones for post-1970 timestamps.  The data entries for
3734    these names are unchanged, so the names continue to work as before.
3735
3736  Changes affecting code internals
3737
3738    zic -c now runs way faster on 64-bit hosts when given large numbers.
3739
3740    zic now uses vfprintf to avoid allocating and freeing some memory.
3741
3742    tzselect now computes the list of continents from the data,
3743    rather than have it hard-coded.
3744
3745    Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
3746
3747  Changes affecting the build procedure
3748
3749    The 'leapseconds' file is now generated automatically from a
3750    new file 'leap-seconds.list', which is a copy of
3751    <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
3752    A new source file 'leapseconds.awk' implements this.
3753    The goal is simplification of the future maintenance of 'leapseconds'.
3754
3755    When building the 'posix' or 'right' subdirectories, if the
3756    subdirectory would be a copy of the default subdirectory, it is
3757    now made a symbolic link if that is supported.  This saves about
3758    2 MB of file system space.
3759
3760    The links America/Shiprock and Antarctica/South_Pole have been
3761    moved to the 'backward' file.  This affects only nondefault builds
3762    that omit 'backward'.
3763
3764  Changes affecting version-control only
3765
3766    .gitignore now ignores 'date'.
3767
3768  Changes affecting documentation and commentary
3769
3770    Changes to the 'tzfile' man page
3771
3772      It now mentions that the binary file format may be extended in
3773      future versions by appending data.
3774
3775      It now refers to the 'zdump' and 'zic' man pages.
3776
3777    Changes to the 'zic' man page
3778
3779      It lists conditions that elicit a warning with '-v'.
3780
3781      It says that the behavior is unspecified when duplicate names
3782      are given, or if the source of one link is the target of another.
3783
3784      Its examples are updated to match the latest data.
3785
3786      The definition of white space has been clarified slightly.
3787      (Thanks to Michael Deckers.)
3788
3789    Changes to the 'Theory' file
3790
3791      There is a new section about the accuracy of the tz database,
3792      describing the many ways that errors can creep in, and
3793      explaining why so many of the pre-1970 timestamps are wrong or
3794      misleading (thanks to Steve Allen, Lester Caine, and Garrett
3795      Wollman for discussions that contributed to this).
3796
3797      The 'Theory' file describes LMT better (this follows a
3798      suggestion by Guy Harris).
3799
3800      It refers to the 2013 edition of POSIX rather than the 2004 edition.
3801
3802      It's mentioned that excluding 'backward' should not affect the
3803      other data, and it suggests at least one zone.tab name per
3804      inhabited country (thanks to Stephen Colebourne).
3805
3806      Some longstanding restrictions on names are documented, e.g.,
3807      'America/New_York' precludes 'America/New_York/Bronx'.
3808
3809      It gives more reasons for the 1970 cutoff.
3810
3811      It now mentions which time_t variants are supported, such as
3812      signed integer time_t.  (Thanks to Paul Goyette for reporting
3813      typos in an experimental version of this change.)
3814
3815      (Thanks to Philip Newton for correcting typos in these changes.)
3816
3817    Documentation and commentary is more careful to distinguish UT in
3818    general from UTC in particular.  (Thanks to Steve Allen.)
3819
3820    Add a better source for the Zurich 1894 transition.
3821    (Thanks to Pierre-Yves Berger.)
3822
3823    Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
3824
3825
3826Release 2013d - 2013-07-05 07:38:01 -0700
3827
3828  Changes affecting future timestamps:
3829
3830    Morocco's midsummer transitions this year are July 7 and August 10,
3831    not July 9 and August 8.  (Thanks to Andrew Paprocki.)
3832
3833    Israel now falls back on the last Sunday of October.
3834    (Thanks to Ephraim Silverberg.)
3835
3836  Changes affecting past timestamps:
3837
3838    Specify Jerusalem's location more precisely; this changes the pre-1880
3839    times by 2 s.
3840
3841  Changing affecting metadata only:
3842
3843    Fix typos in the entries for country codes BQ and SX.
3844
3845  Changes affecting code:
3846
3847    Rework the code to fix a bug with handling Australia/Macquarie on
3848    32-bit hosts (thanks to Arthur David Olson).
3849
3850    Port to platforms like NetBSD, where time_t can be wider than long.
3851
3852    Add support for testing time_t types other than the system's.
3853    Run 'make check_time_t_alternatives' to try this out.
3854    Currently, the tests fail for unsigned time_t;
3855    this should get fixed at some point.
3856
3857  Changes affecting documentation and commentary:
3858
3859    Deemphasize the significance of national borders.
3860
3861    Update the zdump man page.
3862
3863    Remove obsolete NOID comment (thanks to Denis Excoffier).
3864
3865    Update several URLs and comments in the web pages.
3866
3867    Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
3868
3869    Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
3870
3871
3872Release 2013c - 2013-04-19 16:17:40 -0700
3873
3874  Changes affecting current and future timestamps:
3875
3876    Palestine observed DST starting March 29, 2013.  (Thanks to
3877    Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
3878    with the predicted rules being the last Thursday in March at 24:00
3879    to the first Friday on or after September 21 at 01:00.
3880
3881    Assume that the recent change to Paraguay's DST rules is permanent,
3882    by moving the end of DST to the 4th Sunday in March every year.
3883    (Thanks to Carlos Raúl Perasso.)
3884
3885  Changes affecting past timestamps:
3886
3887    Fix some historical data for Palestine to agree with that of
3888    timeanddate.com, as follows:
3889
3890	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
3891	  00:00 Apr 1.
3892
3893	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
3894	  02:00.
3895
3896	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
3897
3898	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
3899
3900	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
3901
3902	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
3903
3904    Fix times of habitation for Macquarie to agree with the Tasmania
3905    Parks & Wildlife Service history, which indicates that permanent
3906    habitation was 1899-1919 and 1948 on.
3907
3908  Changing affecting metadata only:
3909
3910    Macquarie Island is politically part of Australia, not Antarctica.
3911    (Thanks to Tobias Conradi.)
3912
3913    Sort Macquarie more-consistently with other parts of Australia.
3914    (Thanks to Tim Parenti.)
3915
3916
3917Release 2013b - 2013-03-10 22:33:40 -0700
3918
3919  Changes affecting current and future timestamps:
3920
3921    Haiti uses US daylight-saving rules this year, and presumably future years.
3922    This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
3923
3924    Paraguay will end DST on March 24 this year.
3925    (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
3926
3927    Morocco does not observe DST during Ramadan;
3928    try to predict Ramadan in Morocco as best we can.
3929    (Thanks to Erik Homoet for the heads-up.)
3930
3931  Changes affecting commentary:
3932
3933    Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
3934    Update URL for Solaris.  Mention Internet RFC 6557.
3935    Update Internet RFCs 2445->5545, 2822->5322.
3936    Switch from FTP to HTTP for Internet RFCs.
3937
3938
3939Release 2013a - 2013-02-27 09:20:35 -0800
3940
3941  Change affecting binary data format:
3942
3943    The zone offset at the end of version-2-format zone files is now
3944    allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
3945
3946  Changes affecting current and future timestamps:
3947
3948    Chile's 2013 rules, and we guess rules for 2014 and later, will be
3949    the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
3950    (Thanks to Steffen Thorsen and Robert Elz.)
3951
3952    New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
3953    (Thanks to Tobias Conradi and Arthur David Olson.)
3954
3955  Many changes affect historical timestamps before 1940.
3956  These were deduced from: Milne J. Civil time. Geogr J. 1899
3957  Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
3958
3959  Changes affecting the code:
3960
3961    Fix zic bug that mishandled Egypt's 2010 changes (this also affected
3962    the data).  (Thanks to Arthur David Olson.)
3963
3964    Fix localtime bug when time_t is unsigned and data files were generated
3965    by a signed time_t system.  (Thanks to Doug Bailey for reporting and
3966    to Arthur David Olson for fixing.)
3967
3968    Allow the email address for bug reports to be set by the packager.
3969    The default is tz@iana.org, as before.  (Thanks to Joseph S. Myers.)
3970
3971    Update HTML checking to be compatible with Ubuntu 12.10.
3972
3973    Check that files are a safe subset of ASCII.  At some point we may
3974    relax this requirement to a safe subset of UTF-8.  Without the
3975    check, some non-UTF-8 encodings were leaking into the distribution.
3976
3977  Commentary changes:
3978
3979    Restore a comment about copyright notices that was inadvertently deleted.
3980    (Thanks to Arthur David Olson.)
3981
3982    Improve the commentary about which districts observe what times
3983    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
3984
3985    Add web page links to tz.js.
3986
3987    Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
3988
3989
3990Release 2012j - 2012-11-12 18:34:49 -0800
3991
3992  Libya moved to CET this weekend, but with DST planned next year.
3993  (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
3994
3995  Signatures now have the extension .asc, not .sign, as that's more
3996  standard.  (Thanks to Phil Pennock.)
3997
3998  The output of 'zdump --version', and of 'zic --version', now
3999  uses a format that is more typical for --version.
4000  (Thanks to Joseph S. Myers.)
4001
4002  The output of 'tzselect --help', 'zdump --help', and 'zic --help'
4003  now uses tz@iana.org rather than the old elsie address.
4004
4005  zic -v now complains about abbreviations that are less than 3
4006  or more than 6 characters, as per Posix.  Formerly, it checked
4007  for abbreviations that were more than 3.
4008
4009  'make public' no longer puts its temporary directory under /tmp,
4010  and uses the just-built zic rather than the system zic.
4011
4012  Various fixes to documentation and commentary.
4013
4014
4015Release 2012i - 2012-11-03 12:57:09 -0700
4016
4017  Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
4018
4019  Linker flags can now be specified via LDFLAGS.
4020  AWK now defaults to 'awk', not 'nawk'.
4021  The shell in tzselect now defaults to /bin/bash, but this can
4022  be overridden by specifying KSHELL.
4023  The main web page now mentions the unofficial GitHub repository.
4024  (Thanks to Mike Frysinger.)
4025
4026  Tarball signatures can now be built by running 'make signatures'.
4027  There are also new makefile rules 'tarballs', 'check_public', and
4028  separate makefile rules for each tarball and signature file.
4029  A few makefile rules are now more portable to strict POSIX.
4030
4031  The main web page now lists the canonical IANA URL.
4032
4033
4034Release 2012h - 2012-10-26 22:49:10 -0700
4035
4036  Bahia no longer has DST.  (Thanks to Kelley Cook.)
4037
4038  Tocantins has DST.  (Thanks to Rodrigo Severo.)
4039
4040  Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
4041
4042  Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
4043
4044  Web page updates.
4045
4046  More C modernization, except that at Arthur David Olson's suggestion
4047  the instances of 'register' were kept.
4048
4049
4050Release 2012g - 2012-10-17 20:59:45 -0700
4051
4052  Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
4053
4054  Palestine fall 2012.  (Thanks to Steffen Thorsen.)
4055
4056  Assume C89.
4057
4058  To attack the version-number problem, this release ships the file
4059  'Makefile' (which contains the release number) in both the tzcode and
4060  the tzdata tarballs.  The two Makefiles are identical, and should be
4061  identical in any matching pair of tarballs, so it shouldn't matter
4062  which order you extract the tarballs.  Perhaps we can come up with a
4063  better version-number scheme at some point; this scheme does have the
4064  virtue of not adding more files.
4065
4066
4067Release 2012f - 2012-09-12 23:17:03 -0700
4068
4069  * australasia (Pacific/Fiji): Fiji DST is October 21 through January
4070    20 this year.  (Thanks to Steffen Thorsen.)
4071
4072
4073Release 2012e - 2012-08-02 20:44:55 -0700
4074
4075  * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
4076    (Thanks to Steffen Thorsen.)
4077
4078  * Use a single version number for both code and data.
4079
4080  * .gitignore: New file.
4081
4082  * Remove trailing white space.
4083
4084
4085Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
4086
4087  Changes for Morocco's timestamps, which take effect in a couple of
4088  hours, along with infrastructure changes to accommodate how the tz
4089  code and data are released on IANA.
4090
4091
4092Release data2012c - 2012-03-27 12:17:25 -0400
4093
4094  africa
4095	Summer time changes for Morocco (to start late April 2012)
4096
4097  asia
4098	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
4099
4100  northamerica
4101	Haiti following US/Canada rules for 2012 (and we're assuming,
4102	for now anyway, for the future).
4103
4104
4105Release 2012b - 2012-03-02 12:29:15 +0700
4106
4107  There is just one change to tzcode2012b (compared with 2012a):
4108  the Makefile that was accidentally included with 2012a has been
4109  replaced with the version that should have been there, which is
4110  identical with the previous version (from tzcode2011i).
4111
4112  There are just two changes in tzdata2012b compared with 2012a.
4113
4114  Most significantly, summer time in Cuba has been delayed 3 weeks
4115  (now starts April 1 rather than March 11).   Since Mar 11 (the old start
4116  date, as listed in 2012a) is just a little over a week away, this
4117  change is urgent.
4118
4119  Less importantly, an excess tab in one of the changes in zone.tab
4120  in 2012a has been removed.
4121
4122
4123Release 2012a - 2012-03-01 18:28:10 +0700
4124
4125  The changes in tzcode2012a (compared to the previous version, 2011i)
4126  are entirely to the README and tz-art.htm and tz-link.htm files, if
4127  none of those concern you, you can ignore the code update.  The changes
4128  reflect the changed addresses for the mailing list and the code and
4129  data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
4130  has been added to tz-link.htm).
4131
4132  In tzdata2012a (compared to the previous release, which was 2011n)
4133  the major changes are:
4134	Chile 2011/2012 and 2012/2013 summer time date adjustments.
4135	Falkland Islands onto permanent summer time (we're assuming for the
4136		foreseeable future, though 2012 is all we're fairly certain of.)
4137	Armenia has abolished Summer Time.
4138	Tokelau jumped the International Date Line back last December
4139		(just the same as their near neighbour, Samoa).
4140	America/Creston is a new zone for a small area of British Columbia
4141	There will be a leapsecond 2012-06-30 23:59:60 UTC.
4142
4143  Other minor changes are:
4144	Corrections to 1918 Canadian summer time end dates.
4145	Updated URL for UK time zone history (in comments)
4146	A few typos in Le Corre's list of free French place names (comments)
4147
4148
4149Release data2011n - 2011-10-30 14:57:54 +0700
4150
4151  There are three changes of note - most urgently, Cuba (America/Havana)
4152  has extended summer time by two weeks, now to end on Nov 13, rather than
4153  the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
4154  (Europe/Tiraspol) decided not to split from the rest of Moldova after
4155  all, and consequently that zone has been removed (again) and reinstated
4156  in the "backward" file as a link to Europe/Chisinau.   And third, the
4157  end date for Fiji's summer time this summer was moved forward from the
4158  earlier planned Feb 26, to Jan 22.
4159
4160  Apart from that, Moldova (MD) returns to a single entry in zone.tab
4161  (and the incorrect syntax that was in the 2011m version of that file
4162  is so fixed - it would have been fixed in a different way had this
4163  change not happened - that's the "missing" sccs version id).
4164
4165
4166Release data2011m - 2011-10-24 21:42:16 +0700
4167
4168  In particular, the typos in comments in the data (2011-11-17 should have
4169  been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
4170  Tim Parenti noted) have been fixed, and the change for Ukraine has been
4171  made in all 4 Ukrainian zones, rather than just Kiev (again, thanks to
4172  Tim Parenti, and also Denys Gavrysh)
4173
4174  In addition, I added Europe/Tiraspol to zone.tab.
4175
4176  This time, all the files have new version numbers...  (including the files
4177  otherwise unchanged in 2011m that were changed in 2011l but didn't get new
4178  version numbers there...)
4179
4180
4181Release data2011l - 2011-10-10 11:15:43 +0700
4182
4183  There are just 2 changes that cause different generated tzdata files from
4184  zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
4185  is included, but commented out.  Compared with the diff I sent out last week,
4186  this version also includes attributions for the sources for the changes
4187  (in much the same format as ado used, but the html tags have not been
4188  checked, verified, or used in any way at all, so if there are errors there,
4189  please let me know.)
4190
4191
4192Release data2011k - 2011-09-20 17:54:03 -0400
4193
4194  [not summarized]
4195
4196
4197Release data2011j - 2011-09-12 09:22:49 -0400
4198
4199  (contemporary changes for Samoa; past changes for Kenya, Uganda, and
4200  Tanzania); there are also two spelling corrections to comments in
4201  the australasia file (with thanks to Christos Zoulas).
4202
4203
4204Release 2011i - 2011-08-29 05:56:32 -0400
4205
4206  [not summarized]
4207
4208
4209Release data2011h - 2011-06-15 18:41:48 -0400
4210
4211  Russia and Curaçao changes
4212
4213
4214Release 2011g - 2011-04-25 09:07:22 -0400
4215
4216  update the rules for Egypt to reflect its abandonment of DST this year
4217
4218
4219Release 2011f - 2011-04-06 17:14:53 -0400
4220
4221  [not summarized]
4222
4223
4224Release 2011e - 2011-03-31 16:04:38 -0400
4225
4226  Morocco, Chile, and tz-link changes
4227
4228
4229Release 2011d - 2011-03-14 09:18:01 -0400
4230
4231  changes that impact present-day timestamps in Cuba, Samoa, and Turkey
4232
4233
4234Release 2011c - 2011-03-07 09:30:09 -0500
4235
4236  These do affect current timestamps in Chile and Annette Island, Canada.
4237
4238
4239Release 2011b - 2011-02-07 08:44:50 -0500
4240
4241  [not summarized]
4242
4243
4244Release 2011a - 2011-01-24 10:30:16 -0500
4245
4246  [not summarized]
4247
4248
4249Release data2010o - 2010-11-01 09:18:23 -0400
4250
4251  change to the end of DST in Fiji in 2011
4252
4253
4254Release 2010n - 2010-10-25 08:19:17 -0400
4255
4256  [not summarized]
4257
4258
4259Release 2010m - 2010-09-27 09:24:48 -0400
4260
4261  Hong Kong, Vostok, and zic.c changes
4262
4263
4264Release 2010l - 2010-08-16 06:57:25 -0400
4265
4266  [not summarized]
4267
4268
4269Release 2010k - 2010-07-26 10:42:27 -0400
4270
4271  [not summarized]
4272
4273
4274Release 2010j - 2010-05-10 09:07:48 -0400
4275
4276  changes for Bahía de Banderas and for version naming
4277
4278
4279Release data2010i - 2010-04-16 18:50:45 -0400
4280
4281  the end of DST in Morocco on 2010-08-08
4282
4283
4284Release data2010h - 2010-04-05 09:58:56 -0400
4285
4286  [not summarized]
4287
4288
4289Release data2010g - 2010-03-24 11:14:53 -0400
4290
4291  [not summarized]
4292
4293
4294Release 2010f - 2010-03-22 09:45:46 -0400
4295
4296  [not summarized]
4297
4298
4299Release data2010e - 2010-03-08 14:24:27 -0500
4300
4301  corrects the Dhaka bug found by Danvin Ruangchan
4302
4303
4304Release data2010d - 2010-03-06 07:26:01 -0500
4305
4306  [not summarized]
4307
4308
4309Release 2010c - 2010-03-01 09:20:58 -0500
4310
4311  changes including KRE's suggestion for earlier initialization of
4312  "goahead" and "goback" structure elements
4313
4314
4315Release code2010a - 2010-02-16 10:40:04 -0500
4316
4317  [not summarized]
4318
4319
4320Release data2010b - 2010-01-20 12:37:01 -0500
4321
4322  Mexico changes
4323
4324
4325Release data2010a - 2010-01-18 08:30:04 -0500
4326
4327  changes to Dhaka
4328
4329
4330Release data2009u - 2009-12-26 08:32:28 -0500
4331
4332  changes to DST in Bangladesh
4333
4334
4335Release 2009t - 2009-12-21 13:24:27 -0500
4336
4337  [not summarized]
4338
4339
4340Release data2009s - 2009-11-14 10:26:32 -0500
4341
4342  (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
4343
4344
4345Release 2009r - 2009-11-09 10:10:31 -0500
4346
4347  "antarctica" and "tz-link.htm" changes
4348
4349
4350Release 2009q - 2009-11-02 09:12:40 -0500
4351
4352  with two corrections as reported by Eric Muller and Philip Newton
4353
4354
4355Release data2009p - 2009-10-23 15:05:27 -0400
4356
4357  Argentina (including San Luis) changes (with the correction from
4358  Mariano Absatz)
4359
4360
4361Release data2009o - 2009-10-14 16:49:38 -0400
4362
4363  Samoa (commentary only), Pakistan, and Bangladesh changes
4364
4365
4366Release data2009n - 2009-09-22 15:13:38 -0400
4367
4368  added commentary for Argentina and a change to the end of DST in
4369  2009 in Pakistan
4370
4371
4372Release data2009m - 2009-09-03 10:23:43 -0400
4373
4374  Samoa and Palestine changes
4375
4376
4377Release data2009l - 2009-08-14 09:13:07 -0400
4378
4379  Samoa (comments only) and Egypt
4380
4381
4382Release 2009k - 2009-07-20 09:46:08 -0400
4383
4384  [not summarized]
4385
4386
4387Release data2009j - 2009-06-15 06:43:59 -0400
4388
4389  Bangladesh change (with a short turnaround since the DST change is
4390  impending)
4391
4392
4393Release 2009i - 2009-06-08 09:21:22 -0400
4394
4395  updating for DST in Bangladesh this year
4396
4397
4398Release 2009h - 2009-05-26 09:19:14 -0400
4399
4400  [not summarized]
4401
4402
4403Release data2009g - 2009-04-20 16:34:07 -0400
4404
4405  Cairo
4406
4407
4408Release data2009f - 2009-04-10 11:00:52 -0400
4409
4410  correct DST in Pakistan
4411
4412
4413Release 2009e - 2009-04-06 09:08:11 -0400
4414
4415  [not summarized]
4416
4417
4418Release 2009d - 2009-03-23 09:38:12 -0400
4419
4420  Morocco, Tunisia, Argentina, and American Astronomical Society changes
4421
4422
4423Release data2009c - 2009-03-16 09:47:51 -0400
4424
4425  change to the start of Cuban DST
4426
4427
4428Release 2009b - 2009-02-09 11:15:22 -0500
4429
4430  [not summarized]
4431
4432
4433Release 2009a - 2009-01-21 10:09:39 -0500
4434
4435  [not summarized]
4436
4437
4438Release data2008i - 2008-10-21 12:10:25 -0400
4439
4440  southamerica and zone.tab files, with Argentina DST rule changes and
4441  United States zone reordering and recommenting
4442
4443
4444Release 2008h - 2008-10-13 07:33:56 -0400
4445
4446  [not summarized]
4447
4448
4449Release 2008g - 2008-10-06 09:03:18 -0400
4450
4451  Fix a broken HTML anchor and update Brazil's DST transitions;
4452  there's also a slight reordering of information in tz-art.htm.
4453
4454
4455Release data2008f - 2008-09-09 22:33:26 -0400
4456
4457  [not summarized]
4458
4459
4460Release 2008e - 2008-07-28 14:11:17 -0400
4461
4462  changes by Arthur David Olson and Jesper Nørgaard Welen
4463
4464
4465Release data2008d - 2008-07-07 09:51:38 -0400
4466
4467  changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
4468
4469
4470Release data2008c - 2008-05-19 17:48:03 -0400
4471
4472  Pakistan, Morocco, and Mongolia
4473
4474
4475Release data2008b - 2008-03-24 08:30:59 -0400
4476
4477  including renaming Asia/Calcutta to Asia/Kolkata, with a backward
4478  link provided
4479
4480
4481Release 2008a - 2008-03-08 05:42:16 -0500
4482
4483  [not summarized]
4484
4485
4486Release 2007k - 2007-12-31 10:25:22 -0500
4487
4488  most importantly, changes to the "southamerica" file based on
4489  Argentina's readoption of daylight saving time
4490
4491
4492Release 2007j - 2007-12-03 09:51:01 -0500
4493
4494  1. eliminate the "P" (parameter) macro;
4495
4496  2. the "noncontroversial" changes circulated on the time zone
4497  mailing list (less the changes to "logwtmp.c");
4498
4499  3. eliminate "too many transition" errors when "min" is used in time
4500  zone rules;
4501
4502  4. changes by Paul Eggert (including updated information for Venezuela).
4503
4504
4505Release data2007i - 2007-10-30 10:28:11 -0400
4506
4507  changes for Cuba and Syria
4508
4509
4510Release 2007h - 2007-10-01 10:05:51 -0400
4511
4512  changes by Paul Eggert, as well as an updated link to the ICU
4513  project in tz-link.htm
4514
4515
4516Release 2007g - 2007-08-20 10:47:59 -0400
4517
4518  changes by Paul Eggert
4519
4520  The "leapseconds" file has been updated to incorporate the most
4521  recent International Earth Rotation and Reference Systems Service
4522  (IERS) bulletin.
4523
4524  There's an addition to tz-art.htm regarding the television show "Medium".
4525
4526
4527Release 2007f - 2007-05-07 10:46:46 -0400
4528
4529  changes by Paul Eggert (including Haiti, Turks and Caicos, and New
4530  Zealand)
4531
4532  changes to zic.c to allow hour values greater than 24 (along with
4533  Paul's improved time value overflow checking)
4534
4535
4536Release 2007e - 2007-04-02 10:11:52 -0400
4537
4538  Syria and Honduras changes by Paul Eggert
4539
4540  zic.c variable renaming changes by Arthur David Olson
4541
4542
4543Release 2007d - 2007-03-20 08:48:30 -0400
4544
4545  changes by Paul Eggert
4546
4547  the elimination of white space at the ends of lines
4548
4549
4550Release 2007c - 2007-02-26 09:09:37 -0500
4551
4552  changes by Paul Eggert
4553
4554
4555Release 2007b - 2007-02-12 09:34:20 -0500
4556
4557  Paul Eggert's proposed change to the quotation handling logic in zic.c.
4558
4559  changes to the commentary in "leapseconds" reflecting the IERS
4560  announcement that there is to be no positive leap second at the end
4561  of June 2007.
4562
4563
4564Release 2007a - 2007-01-08 12:28:29 -0500
4565
4566  changes by Paul Eggert
4567
4568  Derick Rethans's Asmara change
4569
4570  Oscar van Vlijmen's Easter Island local mean time change
4571
4572  symbolic link changes
4573
4574
4575Release 2006p - 2006-11-27 08:54:27 -0500
4576
4577  changes by Paul Eggert
4578
4579
4580Release 2006o - 2006-11-06 09:18:07 -0500
4581
4582  changes by Paul Eggert
4583
4584
4585Release 2006n - 2006-10-10 11:32:06 -0400
4586
4587  changes by Paul Eggert
4588
4589
4590Release 2006m - 2006-10-02 15:32:35 -0400
4591
4592  changes for Uruguay, Palestine, and Egypt by Paul Eggert
4593
4594  (minimalist) changes to zic.8 to clarify "until" information
4595
4596
4597Release data2006l - 2006-09-18 12:58:11 -0400
4598
4599  Paul's best-effort work on this coming weekend's Egypt time change
4600
4601
4602Release 2006k - 2006-08-28 12:19:09 -0400
4603
4604  changes by Paul Eggert
4605
4606
4607Release 2006j - 2006-08-21 09:56:32 -0400
4608
4609  changes by Paul Eggert
4610
4611
4612Release code2006i - 2006-08-07 12:30:55 -0400
4613
4614  localtime.c fixes
4615
4616  Ken Pizzini's conversion script
4617
4618
4619Release code2006h - 2006-07-24 09:19:37 -0400
4620
4621  adds public domain notices to four files
4622
4623  includes a fix for transition times being off by a second
4624
4625  adds a new recording to the "arts" file (information courtesy Colin Bowern)
4626
4627
4628Release 2006g - 2006-05-08 17:18:09 -0400
4629
4630  northamerica changes by Paul Eggert
4631
4632
4633Release 2006f - 2006-05-01 11:46:00 -0400
4634
4635  a missing version number problem is fixed (with thanks to Bradley
4636  White for catching the problem)
4637
4638
4639Release 2006d - 2006-04-17 14:33:43 -0400
4640
4641  changes by Paul Eggert
4642
4643  added new items to tz-arts.htm that were found by Paul
4644
4645
4646Release 2006c - 2006-04-03 10:09:32 -0400
4647
4648  two sets of data changes by Paul Eggert
4649
4650  a fencepost error fix in zic.c
4651
4652  changes to zic.c and the "europe" file to minimize differences
4653  between output produced by the old 32-bit zic and the new 64-bit
4654  version
4655
4656
4657Release 2006b - 2006-02-20 10:08:18 -0500
4658  [tz32code2006b + tz64code2006b + tzdata2006b]
4659
4660  64-bit code
4661
4662  All SCCS IDs were bumped to "8.1" for this release.
4663
4664
4665Release 2006a - 2006-01-30 08:59:31 -0500
4666
4667  changes by Paul Eggert (in particular, Indiana time zone moves)
4668
4669  an addition to the zic manual page to describe how special-case
4670  transitions are handled
4671
4672
4673Release 2005r - 2005-12-27 09:27:13 -0500
4674
4675  Canadian changes by Paul Eggert
4676
4677  They also add "<pre>" directives to time zone data files and reflect
4678  changes to warning message logic in "zdump.c" (but with calls to
4679  "gettext" kept unbundled at the suggestion of Ken Pizzini).
4680
4681
4682Release 2005q - 2005-12-13 09:17:09 -0500
4683
4684  Nothing earth-shaking here:
4685	1.  Electronic mail addresses have been removed.
4686	2.  Casts of the return value of exit have been removed.
4687	3.  Casts of the argument of is.* macros have been added.
4688	4.  Indentation in one section of zic.c has been fixed.
4689	5.  References to dead URLs in the data files have been dealt with.
4690
4691
4692Release 2005p - 2005-12-05 10:30:53 -0500
4693
4694  "systemv", "tz-link.htm", and "zdump.c" changes
4695  (less the casts of arguments to the is* macros)
4696
4697
4698Release 2005o - 2005-11-28 10:55:26 -0500
4699
4700  Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
4701
4702  zdump.c lint fixes by Arthur David Olson
4703
4704
4705Release 2005n - 2005-10-03 09:44:09 -0400
4706
4707  changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
4708  et al. changes)
4709
4710
4711Release 2005m - 2005-08-29 12:15:40 -0400
4712
4713  changes by Paul Eggert (with a small tweak to the tz-art change)
4714
4715  a declaration of an unused variable has been removed from zdump.c
4716
4717
4718Release 2005l - 2005-08-22 12:06:39 -0400
4719
4720  changes by Paul Eggert
4721
4722  overflow/underflow checks by Arthur David Olson, minus changes to
4723  the "Theory" file about the pending addition of 64-bit data (I grow
4724  less confident of the changes being accepted with each passing day,
4725  and the changes no longer increase the data files nine-fold--there's
4726  less than a doubling in size by my local Sun's reckoning)
4727
4728
4729Release 2005k - 2005-07-14 14:14:24 -0400
4730
4731  The "leapseconds" file has been edited to reflect the recently
4732  announced leap second at the end of 2005.
4733
4734  I've also deleted electronic mail addresses from the files as an
4735  anti-spam measure.
4736
4737
4738Release 2005j - 2005-06-13 14:34:13 -0400
4739
4740  These reflect changes to limit the length of time zone abbreviations
4741  and the characters used in those abbreviations.
4742
4743  There are also changes to handle POSIX-style "quoted" timezone
4744  environment variables.
4745
4746  The changes were circulated on the time zone mailing list; the only
4747  change since then was the removal of a couple of minimum-length of
4748  abbreviation checks.
4749
4750
4751Release data2005i - 2005-04-21 15:04:16 -0400
4752
4753  changes (most importantly to Nicaragua and Haiti) by Paul Eggert
4754
4755
4756Release 2005h - 2005-04-04 11:24:47 -0400
4757
4758  changes by Paul Eggert
4759
4760  minor changes to Makefile and zdump.c to produce more useful output
4761  when doing a "make typecheck"
4762
4763
4764Release 2005g - 2005-03-14 10:11:21 -0500
4765
4766  changes by Paul Eggert (a change to current DST rules in Uruguay and
4767  an update to a link to time zone software)
4768
4769
4770Release 2005f - 2005-03-01 08:45:32 -0500
4771
4772  data and documentation changes by Paul Eggert
4773
4774
4775Release 2005e - 2005-02-10 15:59:44 -0500
4776
4777  [not summarized]
4778
4779
4780Release code2005d - 2005-01-31 09:21:47 -0500
4781
4782  make zic complain about links to links if the -v flag is used
4783
4784  have "make public" do more code checking
4785
4786  add an include to "localtime.c" for the benefit of gcc systems
4787
4788
4789Release 2005c - 2005-01-17 18:36:29 -0500
4790
4791  get better results when mktime runs on a system where time_t is double
4792
4793  changes to the data files (most importantly to Paraguay)
4794
4795
4796Release 2005b - 2005-01-10 09:19:54 -0500
4797
4798  Get localtime and gmtime working on systems with exotic time_t types.
4799
4800  Update the leap second commentary in the "leapseconds" file.
4801
4802
4803Release 2005a - 2005-01-01 13:13:44 -0500
4804
4805  [not summarized]
4806
4807
4808Release code2004i - 2004-12-14 13:42:58 -0500
4809
4810  Deal with systems where time_t is unsigned.
4811
4812
4813Release code2004h - 2004-12-07 11:40:18 -0500
4814
4815  64-bit-time_t changes
4816
4817
4818Release 2004g - 2004-11-02 09:06:01 -0500
4819
4820  update to Cuba (taking effect this weekend)
4821
4822  other changes by Paul Eggert
4823
4824  correction of the spelling of Oslo
4825
4826  changed versions of difftime.c and private.h
4827
4828
4829Release code2004f - 2004-10-21 10:25:22 -0400
4830
4831  Cope with wide-ranging tm_year values.
4832
4833
4834Release 2004e - 2004-10-11 14:47:21 -0400
4835
4836  Brazil/Argentina/Israel changes by Paul Eggert
4837
4838  changes to tz-link.htm by Paul
4839
4840  one small fix to Makefile
4841
4842
4843Release 2004d - 2004-09-22 08:27:29 -0400
4844
4845  Avoid overflow problems when TM_YEAR_BASE is added to an integer.
4846
4847
4848Release 2004c - 2004-08-11 12:06:26 -0400
4849
4850  asctime-related changes
4851
4852  (variants of) some of the documentation changes suggested by Paul Eggert
4853
4854
4855Release 2004b - 2004-07-19 14:33:35 -0400
4856
4857  data changes by Paul Eggert - most importantly, updates for Argentina
4858
4859
4860Release 2004a - 2004-05-27 12:00:47 -0400
4861
4862  changes by Paul Eggert
4863
4864  Handle DST transitions that occur at the end of a month in some
4865  years but at the start of the following month in other years.
4866
4867  Add a copy of the correspondence that's the basis for claims about
4868  DST in the Navajo Nation.
4869
4870
4871Release 2003e - 2003-12-15 09:36:47 -0500
4872
4873  changes by Arthur David Olson (primarily code changes)
4874
4875  changes by Paul Eggert (primarily data changes)
4876
4877  minor changes to "Makefile" and "northamerica" (in the latter case,
4878  optimization of the "Toronto" rules)
4879
4880
4881Release 2003d - 2003-10-06 09:34:44 -0400
4882
4883  changes by Paul Eggert
4884
4885
4886Release 2003c - 2003-09-16 10:47:05 -0400
4887
4888  Fix bad returns in zic.c's inleap function.
4889  Thanks to Bradley White for catching the problem!
4890
4891
4892Release 2003b - 2003-09-16 07:13:44 -0400
4893
4894  Add a "--version" option (and documentation) to the zic and zdump commands.
4895
4896  changes to overflow/underflow checking in zic
4897
4898  a localtime typo fix.
4899
4900  Update the leapseconds and tz-art.htm files.
4901
4902
4903Release 2003a - 2003-03-24 09:30:54 -0500
4904
4905  changes by Paul Eggert
4906
4907  a few additions and modifications to the tz-art.htm file
4908
4909
4910Release 2002d - 2002-10-15 13:12:42 -0400
4911
4912  changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
4913
4914  There's also a new time zone quote in "tz-art.htm".
4915
4916
4917Release 2002c - 2002-04-04 11:55:20 -0500
4918
4919  changes by Paul Eggert
4920
4921  Change zic.c to avoid creating symlinks to files that don't exist.
4922
4923
4924Release 2002b - 2002-01-28 12:56:03 -0500
4925
4926  [These change notes are for Release 2002a, which was corrupted.
4927  2002b was a corrected version of 2002a.]
4928
4929  changes by Paul Eggert
4930
4931  Update the "leapseconds" file to note that there'll be no leap
4932  second at the end of June, 2002.
4933
4934  Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
4935
4936  Change to "difftime.c" to avoid sizeof problems.
4937
4938
4939Release 2001d - 2001-10-09 13:31:32 -0400
4940
4941  changes by Paul Eggert
4942
4943
4944Release 2001c - 2001-06-05 13:59:55 -0400
4945
4946  changes by Paul Eggert and Andrew Brown
4947
4948
4949Release 2001b - 2001-04-05 16:44:38 -0400
4950
4951  changes by Paul Eggert (modulo jnorgard's typo fix)
4952
4953  tz-art.htm has been HTMLified.
4954
4955
4956Release 2001a - 2001-03-13 12:57:44 -0500
4957
4958  changes by Paul Eggert
4959
4960  An addition to the "leapseconds" file: comments with the text of the
4961  latest IERS leap second notice.
4962
4963  Trailing white space has been removed from data file lines, and
4964  repeated spaces in "Rule Jordan" lines in the "asia" file have been
4965  converted to tabs.
4966
4967
4968Release 2000h - 2000-12-14 15:33:38 -0500
4969
4970  changes by Paul Eggert
4971
4972  one typo fix in the "art" file
4973
4974  With providence, this is the last update of the millennium.
4975
4976
4977Release 2000g - 2000-10-10 11:35:22 -0400
4978
4979  changes by Paul Eggert
4980
4981  correction of John Mackin's name submitted by Robert Elz
4982
4983  Garry Shandling's Daylight Saving Time joke (!?!) from the recent
4984  Emmy Awards broadcast.
4985
4986
4987Release 2000f - 2000-08-10 09:31:58 -0400
4988
4989  changes by Paul Eggert
4990
4991  Added information in "tz-art.htm" on a Seinfeld reference to DST.
4992
4993  Error checking and messages in the "yearistype" script have been
4994  improved.
4995
4996
4997Release 2000e - 2000-07-31 09:27:54 -0400
4998
4999  data changes by Paul Eggert
5000
5001  a change to the default value of the defined constant HAVE_STRERROR
5002
5003  the addition of a Dave Barry quote on DST to the tz-arts file
5004
5005
5006Release 2000d - 2000-04-20 15:43:04 -0400
5007
5008  changes to the documentation and code of strftime for C99 conformance
5009
5010  a bug fix for date.c
5011
5012  These are based on (though modified from) changes by Paul Eggert.
5013
5014
5015Release 2000c - 2000-03-04 10:31:43 -0500
5016
5017  changes by Paul Eggert
5018
5019
5020Release 2000b - 2000-02-21 12:16:29 -0500
5021
5022  changes by Paul Eggert and Joseph Myers
5023
5024  modest tweaks to the tz-art.htm and tz-link.htm files
5025
5026
5027Release 2000a - 2000-01-18 09:21:26 -0500
5028
5029  changes by Paul Eggert
5030
5031  The two hypertext documents have also been renamed.
5032
5033
5034Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
5035
5036  Paul Eggert's changes
5037
5038  additions to the "zic" manual page and the "Arts.htm" file
5039
5040
5041Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
5042
5043  [not summarized]
5044
5045
5046Release data1999h - 1999-10-07 03:50:29 -0400
5047
5048  changes by Paul Eggert to "europe" (most importantly, fixing
5049  Lithuania and Estonia)
5050
5051
5052Release 1999g - 1999-09-28 11:06:18 -0400
5053
5054  data changes by Paul Eggert (most importantly, the change for
5055  Lebanon that buys correctness for this coming Sunday)
5056
5057  The "code" file contains changes to "Makefile" and "checktab.awk" to
5058  allow better checking of time zone files before they are published.
5059
5060
5061Release 1999f - 1999-09-23 09:48:14 -0400
5062
5063  changes by Arthur David Olson and Paul Eggert
5064
5065
5066Release 1999e - 1999-08-17 15:20:54 -0400
5067
5068  changes circulated by Paul Eggert, although the change to handling
5069  of DST-specifying timezone names has been commented out for now
5070  (search for "XXX" in "localtime.c" for details).  These files also
5071  do not make any changes to the start of DST in Brazil.
5072
5073  In addition to Paul's changes, there are updates to "Arts.htm" and
5074  cleanups of URLs.
5075
5076
5077Release 1999d - 1999-03-30 11:31:07 -0500
5078
5079  changes by Paul Eggert
5080
5081  The Makefile's "make public" rule has also been changed to do a test
5082  compile of each individual time zone data file (which should help
5083  avoid problems such as the one we had with Nicosia).
5084
5085
5086Release 1999c - 1999-03-25 09:47:47 -0500
5087
5088  changes by Paul Eggert, most importantly the change for Chile.
5089
5090
5091Release 1999b - 1999-02-01 17:51:44 -0500
5092
5093  changes by Paul Eggert
5094
5095  code changes (suggested by Mani Varadarajan, mani at be.com) for
5096  correct handling of symbolic links when building using a relative directory
5097
5098  code changes to generate correct messages for failed links
5099
5100  updates to the URLs in Arts.htm
5101
5102
5103Release 1999a - 1999-01-19 16:20:29 -0500
5104
5105  error message internationalizations and corrections in zic.c and
5106  zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
5107  to whom thanks!)
5108
5109
5110Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
5111
5112  changes for Brazil, Chile, and Germany
5113
5114  support for use of "24:00" in the input files for the time zone compiler
5115
5116
5117Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
5118
5119  changes by Paul Eggert
5120
5121  correction to a define in the "private.h" file
5122
5123
5124Release data1998g - 1998-08-11 03:28:35 -0000
5125  [tzdata1998g.tar.gz is missing!]
5126
5127  Lithuanian change provided by mgedmin at pub.osf.it
5128
5129  Move creation of the GMT link with Etc/GMT to "etcetera" (from
5130  "backward") to ensure that the GMT file is created even where folks
5131  don't want the "backward" links (as suggested by Paul Eggert).
5132
5133
5134Release data1998f - 1998-07-20 13:50:00 -0000
5135  [tzdata1998f.tar.gz is missing!]
5136
5137  Update the "leapseconds" file to include the newly-announced
5138  insertion at the end of 1998.
5139
5140
5141Release code1998f - 1998-06-01 10:18:31 -0400
5142
5143  addition to localtime.c by Guy Harris
5144
5145
5146Release 1998e - 1998-05-28 09:56:26 -0400
5147
5148  The Makefile is changed to produce zoneinfo-posix rather than
5149  zoneinfo/posix, and to produce zoneinfo-leaps rather than
5150  zoneinfo/right.
5151
5152  data changes by Paul Eggert
5153
5154  changes from Guy Harris to provide asctime_r and ctime_r
5155
5156  A usno1998 file (substantially identical to usno1997) has been added.
5157
5158
5159Release 1998d - 1998-05-14 11:58:34 -0400
5160
5161  changes to comments (in particular, elimination of references to CIA maps).
5162  "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
5163  where changes occur.
5164
5165
5166Release 1998c - 1998-02-28 12:32:26 -0500
5167
5168  changes by Paul Eggert (save the "French correction," on which I'll
5169  wait for the dust to settle)
5170
5171  symlink changes
5172
5173  changes and additions to Arts.htm
5174
5175
5176Release 1998b - 1998-01-17 14:31:51 -0500
5177
5178  URL cleanups and additions
5179
5180
5181Release 1998a - 1998-01-13 12:37:35 -0500
5182
5183  changes by Paul Eggert
5184
5185
5186Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
5187
5188  changes by Paul Eggert, with minor modifications from Arthur David
5189  Olson to make the files more browser friendly
5190
5191
5192Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
5193
5194  minor changes to put "TZif" at the start of each timezone information file
5195
5196  a rule has also been added to the Makefile so you can
5197	make zones
5198  to just recompile the zone information files (rather than doing a
5199  full "make install" with its other effects).
5200
5201
5202Release data1997i - 1997-10-07 08:45:38 -0400
5203
5204  changes to Africa by Paul Eggert
5205
5206
5207Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
5208
5209  corrections for Uruguay (and other locations)
5210
5211  Arthur David Olson's simple-minded fix allowing mktime to both
5212  correctly handle leap seconds and correctly handle tm_sec values
5213  upon which arithmetic has been performed.
5214
5215
5216Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
5217
5218  Paul Eggert's updates
5219
5220  a small change to a function prototype;
5221
5222  "Music" has been renamed "Arts.htm", HTMLified, and augmented to
5223  include information on Around the World in Eighty Days.
5224
5225
5226Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
5227
5228  fixes to zic's error handling
5229
5230  changes inspired by the item circulated on Slovenia
5231
5232  The description of Web resources has been HTMLified for browsing
5233  convenience.
5234
5235  A new piece of tz-related music has been added to the "Music" file.
5236
5237
5238Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
5239
5240  Paul Eggert's latest suggestions
5241
5242
5243Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
5244
5245  changes to "zic.c" to correct performance of the "-s" option
5246
5247  a new file "usno1997"
5248
5249
5250Release data1997c - 1997-03-04 09:58:18 -0500
5251
5252  changes in Israel
5253
5254
5255Release 1997b - 1997-02-27 18:34:19 -0500
5256
5257  The data file incorporates the 1997 leap second.
5258
5259  The code file incorporates Arthur David Olson's take on the
5260  zic/multiprocessor/directory-creation situation.
5261
5262
5263Release 1997a - 1997-01-21 09:11:10 -0500
5264
5265  Paul Eggert's Antarctica (and other changes)
5266
5267  Arthur David Olson finessed the "getopt" issue by checking against
5268  both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
5269  is returned while SunOS 5.5's manual says EOF is returned).
5270
5271
5272Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
5273
5274  Paul Eggert's latest changes
5275
5276
5277Release code1996n - 1996-12-16 09:42:02 -0500
5278
5279  link snapping fix from Bruce Evans (via Garrett Wollman)
5280
5281
5282Release data1996m - 1996-11-24 02:37:34 -0000
5283  [tzdata1996m.tar.gz is missing!]
5284
5285  Paul Eggert's batch of changes
5286
5287
5288Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
5289
5290  No functional changes here; the files have simply been changed to
5291  make more use of ISO style dates in comments. The names of the above
5292  files now include the year in full.
5293
5294
5295Release code96l - 1996-09-08 17:12:20 -0400
5296
5297  tzcode96k was missing a couple of pieces.
5298
5299
5300Release 96k - 1996-09-08 16:06:22 -0400
5301
5302  the latest round of changes from Paul Eggert
5303
5304  the recent Year 2000 material
5305
5306
5307Release code96j - 1996-07-30 13:18:53 -0400
5308
5309  Set sp->typecnt as suggested by Timothy Patrick Murphy.
5310
5311
5312Release code96i - 1996-07-27 20:11:35 -0400
5313
5314  Paul's suggested patch for strftime %V week numbers
5315
5316
5317Release data96i - 1996-07-01 18:13:04 -0400
5318
5319  "northamerica" and "europe" changes by Paul Eggert
5320
5321
5322Release code96h - 1996-06-05 08:02:21 -0400
5323
5324  fix for handling transitions specified in Universal Time
5325
5326  Some "public domain" notices have also been added.
5327
5328
5329Release code96g - 1996-05-16 14:00:26 -0400
5330
5331  fix for the simultaneous-DST-and-zone-change challenge
5332
5333
5334Release data96h - 1996-05-09 17:40:51 -0400
5335
5336  changes by Paul Eggert
5337
5338
5339Release code96f-data96g - 1996-05-03 03:09:59 -0000
5340  [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
5341
5342  The changes get us some of the way to fixing the problems noted in Paul
5343  Eggert's letter yesterday (in addition to a few others).  The approach
5344  has been to make zic a bit smarter about figuring out what time zone
5345  abbreviations apply just after the time specified in the "UNTIL" part
5346  of a zone line.  Putting the smarts in zic means avoiding having
5347  transition times show up in both "Zone" lines and "Rule" lines, which
5348  in turn avoids multiple transition time entries in time zone files.
5349  (This also makes the zic input files such as "europe" a bit shorter and
5350  should ease maintenance.)
5351
5352
5353Release data96f - 1996-04-19 19:20:03 -0000
5354  [tzdata96f.tar.gz is missing!]
5355
5356  The only changes are to the "northamerica" file; the time zone
5357  abbreviation for Denver is corrected to MST (and MDT), and the
5358  comments for Mexico have been updated.
5359
5360
5361Release data96e - 1996-03-19 17:37:26 -0500
5362
5363  Proposals by Paul Eggert, in particular the Portugal change that
5364  comes into play at the end of this month.
5365
5366
5367Release data96d - 1996-03-18 20:49:39 -0500
5368
5369  [not summarized]
5370
5371
5372Release code96e - 1996-02-29 15:43:27 -0000
5373  [tzcode96e.tar.gz is missing!]
5374
5375  internationalization changes and the fix to the documentation for strftime
5376
5377
5378Release code96d-data96c - 1996-02-12 11:05:27 -0500
5379
5380  The "code" file simply updates Bob Kridle's electronic address.
5381
5382  The "data" file updates rules for Mexico.
5383
5384
5385Release data96b - 1996-01-27 15:44:42 -0500
5386
5387  Kiribati change
5388
5389
5390Release code96c - 1996-01-16 16:58:15 -0500
5391
5392  leap-year streamlining and binary-search changes
5393
5394  fix to newctime.3
5395
5396
5397Release code96b - 1996-01-10 20:42:39 -0500
5398
5399  fixes and enhancements from Paul Eggert, including code that
5400  emulates the behavior of recent versions of the SunOS "date"
5401  command.
5402
5403
5404Release 96a - 1996-01-06 09:08:24 -0500
5405
5406  Israel updates
5407
5408  fixes to strftime.c for correct ISO 8601 week number generation,
5409  plus support for two new formats ('G' and 'g') to give ISO 8601 year
5410  numbers (which are not necessarily the same as calendar year numbers)
5411
5412
5413Release code95i-data95m - 1995-12-21 12:46:47 -0500
5414
5415  The latest revisions from Paul Eggert are included, the usno1995
5416  file has been updated, and a new file ("WWW") covering useful URLs
5417  has been added.
5418
5419
5420Release code95h-data95l - 1995-12-19 18:10:12 -0500
5421
5422  A simplification of a macro definition, a change to data for Sudan,
5423  and (for last minute shoppers) notes in the "Music" file on the CD
5424  "Old Man Time".
5425
5426
5427Release code95g-data95k - 1995-10-30 10:32:47 -0500
5428
5429  (slightly reformatted) 8-bit-clean proposed patch
5430
5431  minor patch: US/Eastern -> America/New_York
5432
5433  snapshot of the USNO's latest data ("usno1995")
5434
5435  some other minor cleanups
5436
5437
5438Release code95f-data95j - 1995-10-28 21:01:34 -0000
5439  [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
5440
5441  European cleanups
5442
5443  support for 64-bit time_t's
5444
5445  optimization in localtime.c
5446
5447
5448Release code95e - 1995-10-13 13:23:57 -0400
5449
5450  the mktime change to scan from future to past when trying to find time zone
5451  offsets
5452
5453
5454Release data95i - 1995-09-26 10:43:26 -0400
5455
5456  For Canada/Central, guess that the Sun customer's "one week too
5457  early" was just a approximation, and the true error is one month
5458  too early.  This is consistent with the rest of Canada.
5459
5460
5461Release data95h - 1995-09-21 11:26:48 -0400
5462
5463  latest changes from Paul Eggert
5464
5465
5466Release code95d - 1995-09-14 11:14:45 -0400
5467
5468  the addition of a "Music" file, which documents four recorded
5469  versions of the tune "Save That Time".
5470
5471
5472Release data95g - 1995-09-01 17:21:36 -0400
5473
5474  "yearistype" correction
5475
5476
5477Release data95f - 1995-08-28 20:46:56 -0400
5478
5479  Paul Eggert's change to the australasia file
5480
5481
5482Release data95e - 1995-07-08 18:02:34 -0400
5483
5484  The only change is a leap second at the end of this year.
5485  Thanks to Bradley White for forwarding news on the leap second.
5486
5487
5488Release data95d - 1995-07-03 13:26:22 -0400
5489
5490  Paul Eggert's changes
5491
5492
5493Release data95c - 1995-07-02 19:19:28 -0400
5494
5495  changes to "asia", "backward", "europe", and "southamerica"
5496  (read: northamericacentrics need not apply)
5497
5498
5499Release code95c - 1995-03-13 14:00:46 -0500
5500
5501  one-line fix for sign extension problems in detzcode
5502
5503
5504Release 95b - 1995-03-04 11:22:38 -0500
5505
5506  Minor changes in both:
5507
5508  The "code" file contains a workaround for the lack of "unistd.h" in
5509  Microsoft C++ version 7.
5510
5511  The "data" file contains a fixed "Link" for America/Shiprock.
5512
5513
5514Release 94h - 1994-12-10 12:51:14 -0500
5515
5516  The files:
5517
5518  *	incorporate the changes to "zdump" and "date" to make changes to
5519	the "TZ" environment variable permanent;
5520
5521  *	incorporate the table changes by Paul Eggert;
5522
5523  *	include (and document) support for universal time specifications in
5524	data files - but do not (yet) include use of this feature in the
5525	data files.
5526
5527  Think of this as "TZ Classic" - the software has been set up not to break if
5528  universal time shows up in its input, and data entries have been
5529  left as is so as not to break existing implementations.
5530
5531
5532Release data94f - 1994-08-20 12:56:09 -0400
5533
5534  (with thanks!) the latest data updates from Paul Eggert
5535
5536
5537Release data94e - 1994-06-04 13:13:53 -0400
5538
5539  [not summarized]
5540
5541
5542Release code94g - 1994-05-05 12:14:07 -0400
5543
5544  fix missing "optind.c" and a reference to it in the Makefile
5545
5546
5547Release code94f - 1994-05-05 13:00:33 -0000
5548  [tzcode94f.tar.gz is missing!]
5549
5550  changes to avoid overflow in difftime, as well as changes to cope
5551  with the 52/53 challenge in strftime
5552
5553
5554Release code94e - 1994-03-30 23:32:59 -0500
5555
5556  change for the benefit of PCTS
5557
5558
5559Release 94d - 1994-02-24 15:42:25 -0500
5560
5561  Avoid clashes with POSIX semantics for zones such as GMT+4.
5562
5563  Some other very minor housekeeping is also present.
5564
5565
5566Release code94c - 1994-02-10 08:52:40 -0500
5567
5568  Fix bug where mkdirs was broken unless you compile with
5569  -fwritable-strings (which is generally losing to do).
5570
5571
5572Release 94b - 1994-02-07 10:04:33 -0500
5573
5574  work by Paul Eggert who notes:
5575
5576  I found another book of time zone histories by E W Whitman; it's not
5577  as extensive as Shanks but has a few goodies of its own.  I used it
5578  to update the tables.  I also fixed some more as a result of
5579  correspondence with Adam David and Peter Ilieve, and move some stray
5580  links from 'europe' to 'backward'.  I corrected some scanning errors
5581  in usno1989.
5582
5583  As far as the code goes, I fixed zic to allow years in the range
5584  INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
5585  And I cleaned up the zic documentation a little bit.
5586
5587
5588Release data94a - 1994-02-03 08:58:54 -0500
5589
5590  It simply incorporates the recently announced leap second into the
5591  "leapseconds" file.
5592
5593
5594Release 93g - 1993-11-22 17:28:27 -0500
5595
5596  Paul Eggert has provided a good deal of historic information (based
5597  on Shanks), and there are some code changes to deal with the buglets
5598  that crawled out in dealing with the new information.
5599
5600
5601Release 93f - 1993-10-15 12:27:46 -0400
5602
5603  Paul Eggert's changes
5604
5605
5606Release 93e - 1993-09-05 21:21:44 -0400
5607
5608  This has updated data for Israel, England, and Kwajalein.  There's
5609  also an update to "zdump" to cope with Kwajalein's 24-hour jump.
5610  Thanks to Paul Eggert and Peter Ilieve for the changes.
5611
5612
5613Release 93d - 1993-06-17 23:34:17 -0400
5614
5615  new fix and new data on Israel
5616
5617
5618Release 93c - 1993-06-06 19:31:55 -0400
5619
5620  [not summarized]
5621
5622
5623Release 93b - 1993-02-02 14:53:58 -0500
5624
5625  updated "leapseconds" file
5626
5627
5628Release 93 - 1993-01-08 07:01:06 -0500
5629
5630  At kre's suggestion, the package has been split in two - a code piece
5631  (which also includes documentation) that's only of use to folks who
5632  want to recompile things and a data piece useful to anyone who can
5633  run "zic".
5634
5635  The new version has a few changes to the data files, a few
5636  portability changes, and an off-by-one fix (with thanks to
5637  Tom Karzes at deshaw.com for providing a description and a
5638  solution).
5639
5640
5641Release 92c - 1992-11-21 17:35:36 -0000
5642  [tz92c.tar.Z is missing!]
5643
5644  The fallout from the latest round of DST transitions.
5645
5646  There are changes for Portugal, Saskatchewan, and "Pacific-New";
5647  there's also a change to "zic.c" that makes it portable to more systems.
5648
5649
5650Release 92 - 1992-04-25 18:17:03 -0000
5651  [tz92.tar.Z is missing!]
5652
5653  By popular demand (well, at any rate, following a request by kre at munnari)
5654
5655
5656The 1989 update of the time zone package featured:
5657
5658  *	POSIXization (including interpretation of POSIX-style TZ environment
5659	variables, provided by Guy Harris),
5660  *	ANSIfication (including versions of "mktime" and "difftime"),
5661  *	SVIDulation (an "altzone" variable)
5662  *	MACHination (the "gtime" function)
5663  *	corrections to some time zone data (including corrections to the rules
5664	for Great Britain and New Zealand)
5665  *	reference data from the United States Naval Observatory for folks who
5666	want to do additional time zones
5667  *	and the 1989 data for Saudi Arabia.
5668
5669  (Since this code will be treated as "part of the implementation" in some
5670  places and as "part of the application" in others, there's no good way to
5671  name functions, such as timegm, that are not part of the proposed ANSI C
5672  standard; such functions have kept their old, underscore-free names in this
5673  update.)
5674
5675  And the "dysize" function has disappeared; it was present to allow
5676  compilation of the "date" command on old BSD systems, and a version of "date"
5677  is now provided in the package.  The "date" command is not created when you
5678  "make all" since it may lack options provided by the version distributed with
5679  your operating system, or may not interact with the system in the same way
5680  the native version does.
5681
5682  Since POSIX frowns on correct leap second handling, the default behavior of
5683  the "zic" command (in the absence of a "-L" option) has been changed to omit
5684  leap second information from its output files.
5685
5686
5687-----
5688Notes
5689
5690This file contains copies of the part of each release announcement
5691that talks about the changes in that release.  The text has been
5692adapted and reformatted for the purposes of this file.
5693
5694Traditionally a release R consists of a pair of tarball files,
5695tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
5696code2010a, data2012c) consist of just one or the other tarball, and a
5697few (e.g., code2012c-data2012d) have tarballs with mixed version
5698numbers.  Recent releases also come in an experimental format
5699consisting of a single tarball tzdb-R.tar.lz with extra data.
5700
5701Release timestamps are taken from the release's commit (for newer,
5702Git-based releases), from the newest file in the tarball (for older
5703releases, where this info is available) or from the email announcing
5704the release (if all else fails; these are marked with a time zone
5705abbreviation of -0000 and an "is missing!" comment).
5706
5707Earlier versions of the code and data were not announced on the tz
5708list and are not summarized here.
5709
5710This file is in the public domain.
5711
5712Local Variables:
5713coding: utf-8
5714End:
5715