2 ms·
If your alarm is set to go off at 7AM London time on Dec 1st, and the UK government decides to shift the UK to UTC+5 for some reason, the alarm still needs to g
by ta1243 3y ago
If your alarm is set to go off at 7AM London time on Dec 1st, and the UK government decides to shift the UK to UTC+5 for some reason, the alarm still needs to go off at 7AM London time, but it's changed from 0700UTC to 0200UTC.
There is no need to inform the user of a change if you have stored the date correctly -- as 7AM London time.
If you had stored the alarm at 0700UTC, you are wrong. You may be lucky and the government doesn't change the time, but just because you are lucky it doesn't mean you are right.
If your user wants to store a date in UTC, that's fine, that's their choice. If they want to store it as London time, that's also fine.
- withinboredom 3y agoYou aren't reading what I wrote. None of this matters if it only affects a single person/organization. It doesn't matter what time zone you are in, it will "just work," the only thing that is different is the amount of effort required by the dev. Even then, there's probably going to be a delay while tzdata is updated downstream and on the servers/phones/etc. It only matters when you have people in multiple timezones. A better analogy would be if you set an alarm to go off 7AM London time, for me, and I am in Amsterdam time. When the UK decides to switch to UTC+5, that 8 AM alarm (CEST) won't go off ... instead it will go off at 13:00 CEST. That is why you need to notify users that have an appointment in a different, affected, timezone.