If I understand [1] correctly, two new zones (or one new one and the old one) would be created in that case. E.g. if Strasbourg would be occupied by Germany in 2027, a new Europe/Strasbourg could be created which has the same rules as Europe/Paris until 2026, and the rules of Europe/Berlin as of 2027.

[1] https://en.wikipedia.org/wiki/Tz_database

--

By the way, I looked up the time zone in Crimea.

> On 29 March 2014, after annexation by Russia, Crimea switched from Eastern European Time (UTC+02:00) to Moscow Time (UTC+04:00 then, subsequently changed to UTC+03:00). [2]

Crimea has its own zone in the IANA database, Europe/Simferopol, which was updated in 2014 (and already existed before, as it already used Moscow time from 1994 to 1997). [3]

[2] https://en.wikipedia.org/wiki/Time_in_Ukraine

[3] https://lists.iana.org/hyperkitty/list/tz@iana.org/thread/DS... https://github.com/eggert/tz/commit/bb203f1bb0b6cd4bb2b08f25... https://github.com/eggert/tz/blob/bb203f1bb0b6cd4bb2b08f2560...