[foepys]

Which production-ready datetime library doesn't use zoneinfo? There should be no need to patch otherwise there would be quite a lot of patching happening each year. The current version is 2021e, meaning it's the 5th iteration for 2021.

Notably Fiji decided to not use DST in 2021/2022 but apparently plans to resume using it afterwards.

[spiffytech]

Any software using an IANA zone (e.g., America/New_York) shouldn't have any trouble. But any software that uses zone labels like EST might do the wrong thing, since EDT is being renamed to EST but will still have EDT's offset.