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r-lib / tzdb

Time Zone Database Information
https://tzdb.r-lib.org
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Update to 2021e #12

Closed DavisVaughan closed 3 years ago

DavisVaughan commented 3 years ago

2021b is late because of various arguments going on in the mailing list https://mm.icann.org/pipermail/tz/2021-September/030400.html

They ended up rolling back most of these changes and releasing a more conservative 2021b release.

The main change is that a few time zones that were the same post-1970 have been merged into the same zone name (keeping the most populous zone as the name). This covers most of the change:

Merge more location-based Zones whose timestamps agree since 1970, as pre-1970 timestamps are out of scope. This is part of a process that has been ongoing since 2013. This does not affect post-1970 timestamps, and timezone historians who build with 'make PACKRATDATA=backzone' should see no changes to pre-1970 timestamps. When merging, keep the most-populous location's data, and move data for other locations to 'backzone' with a backward link in 'backward'. For example, move America/Creston data to 'backzone' with a link in 'backward' from America/Phoenix because the two timezones' timestamps agree since 1970; this change affects some pre-1968 timestamps in America/Creston because Creston and Phoenix disagreed before 1968. The affected Zones are Africa/Accra, America/Atikokan, America/Blanc-Sablon, America/Creston, America/Curacao, America/Nassau, America/Port_of_Spain, Antarctica/DumontDUrville, and Antarctica/Syowa.

May have to wait until the windowsZones file is updated by https://github.com/unicode-org/cldr

DavisVaughan commented 3 years ago

We are now up to 2021e

Nodatime seems to release even with an old mapping file, so it seems okay. That mapping file only gets updated around 2 times per year.