Tags: python/tzdata
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Update tzdata to version 2026d (#153) # Version 2026.4 Upstream version 2026d released 2026-09-11T22:21:07+00:00 ## Briefly: Canada’s Northwest Territories moved to permanent -06 on 2026-08-21. Obsolescent settings like TZ="EST5EDT" now conform better to POSIX. Fix security, performance and porting bugs in zic and localtime. ## Changes to future timestamps Canada’s Northwest Territories will not fall back on 2026-11-01 and will stay on -06 year-round, matching Alberta’s recent change. Model this with its traditional abbreviation CST. Although the change to permanent -06 legally took place on 2026-08-21, temporarily model the change to occur on 2026-11-01 at 02:00 for the same reason as other recent temporary hacks. (Caution: see “NOTE FOR 2026b TEMPORARY HACK FOR CLDR AND CANADA” below.) This affects only America/Inuvik as the rest of the territory is covered by America/Edmonton, for which the equivalent change was released in 2026c. ## Changes to past timestamps Colombia’s 1992-05-02 spring forward was at 00:00, not 24:00. Iran’s 1979-05-26 spring forward was at 00:00, not 24:00. (Thanks to N.F. Hase.) The backward-compatibility names EST5EDT, CST6CDT, MST7MDT, and PST8PDT now conform better to POSIX. For example, EST5EDT now always uses the abbreviation "EST" for standard time (now always 5 hours behind UT) and "EDT" for daylight saving time, whereas it formerly had different UT offsets before standard time was introduced and sometimes used abbreviations like "LMT", "EWT" and "EPT", all contrary to POSIX. Also, though not required by POSIX these names now use US federal rules rather than rules of places like New York, reverting to 2024a behavior. This change affects only timestamps before 1966-10-30 at 01:00 standard time. ## Other data changes The temporary hacks used for North American timekeeping changes now work around a libstdc++ std::chrono bug in GCC 14.1-14.4, 15.1-15.2, and 16.1; see GCC bug 124851. This data change does not affect TZif files or timestamps. The change does not work around the related but less serious GCC bugs 116110 and 124513. These GCC bugs are all fixed in GCC 16.2. ## Changes to documentation URLs for release tarballs in tz-link.html have been updated to reflect their new canonical URLs on data.iana.org. Co-authored-by: Stan Ulbrych <stan@python.org>
Update tzdata to version `2026c` (#145) # Version 2026.3 Upstream version 2026c released 2026-07-08T17:23:58+00:00 ## Briefly: Alberta moved to permanent -06 on 2026-06-18. Morocco moves to permanent +00 on 2026-09-20. More integer overflow bugs have been fixed in zic. ## Changes to future timestamps Alberta’s 2026-03-08 spring forward was its last foreseeable clock change, as it moved to permanent -06 thereafter. (Thanks to Roozbeh Pournader and others.) Model this with its traditional abbreviation CST. Although the change to permanent -06 legally took place on 2026-06-18, temporarily model the change to occur on 2026-11-01 at 02:00 instead, for the same reason we introduced a similarly temporary hack for British Columbia in 2026b. Although another TZDB release will likely be needed soon because Northwest Territories will likely follow Alberta, the legal formalities have not yet taken place. Morocco plans to move back to permanent UTC, without daylight saving time transitions, on 2026-09-20 at 02:00. This also affects Western Sahara. ## Changes to commentary Northwest Territories is expected to move to permanent -06 prior to 2026-11-01 02:00, when clocks would otherwise fall back. (Thanks to Tim Parenti and James Bellaire.) Model this with its traditional abbreviation CST. Unfortunately the change is not yet official, so it is currently present only as comments that can be uncommented as needed. Co-authored-by: Stan Ulbrych <stan@python.org>
Update tzdata to version '2026b' (#135) # Version 2026.2 Upstream version 2026b released 2026-04-23T06:06:43+00:00 ## Briefly: British Columbia moved to permanent -07 on 2026-03-09. Some more overflow bugs have been fixed in zic. ## Changes to future timestamps British Columbia’s 2026-03-08 spring forward was its last foreseeable clock change, as it moved to permanent -07 thereafter. (Thanks to Arthur David Olson.) Although the change to permanent -07 legally took place on 2026-03-09, temporarily model the change to occur on 2026-11-01 at 02:00 instead. This works around a limitation in CLDR v48.2 (2026-03-17). This temporary hack is planned to be removed after CLDR is fixed.
Update tzdata to version '2026a' (#123) # Version 2026.1 Upstream version 2026a released 2026-03-02T06:59:49+00:00 ## Briefly: Moldova has used EU transition times since 2022. The "right" TZif files are no longer installed by default. -DTZ_RUNTIME_LEAPS=0 disables runtime support for leap seconds. TZif files are no longer limited to 50 bytes of abbreviations. zic is no longer limited to 50 leap seconds. Several integer overflow bugs have been fixed. ## Changes to past and future timestamps Since 2022 Moldova has observed EU transition times, that is, it has sprung forward at 03:00, not 02:00, and has fallen back at 04:00, not 03:00. (Thanks to Heitor David Pinto.) ## Changes to data Remove Europe/Chisinau from zonenow.tab, as it now agrees with Europe/Athens for future timestamps. Co-authored-by: Stan Ulbrych <stan@python.org>
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