> Well, how do we know what timezone is "2026-06-19 07:00" in, to be able to know that the time rules for that timezone have changed, if we do not store the timezone?

The website uses their system timezone America/Los_Angeles. It would be better to store that as well, but it's probably not much of an issue if the website is dedicated to meetings in that specific locale.

> Additionally, how do we really "detect that the time rules for that timezone have changed"? We can stay informed, sure, but is there a way to automate this?

My first attempt would be to diff the data between versions. If a diff of 2025b against 2025a has added/removed lines which include America/Los_Angeles, you recompute the timestamps. This, of course, requires that the library support multiple timezone database versions at once.