please use a built-in database for DST

[0xRustlang]

Hello

In several days, many countries including many ones in Europe will stop switching to Daylight Saving Time (DST) A.K.A Summer Time.

Those who have old devices that won't get updates (and maybe use them as an alarm clock or other use cases) cannot force the phone to use a custom Time-Zone and if they set the Time manually, still that will be rationally irrelevant.

Let's say someone's phone in Netherlands will switch to summer time automatically (this will happen even if that person have set the time to not sync with NTP servers)

So, the Timezone of his phone will become "GMT + 2" instead of 1.

Then if that person changes the time manually, it will be rationally incorrect for websites and services and some time critical services.

Because their time zone is one hour ahead but their clock has been set manually to one hour less.

So they have no choice other than let the time of their phone change like previous years.

this can get resolved with using UTC mode but those that are in places that have half hour in their Timezone will have trouble as setting time based on UTC doesn't provide UTC + 1:30 and such.

There is another issue and that is because your app uses the database of the phone for World clock, it shows the clock of some other countries also incorrectly as the phone isn't updated to include their new DST stopping state.

Your clock app also shows the time incorrectly and also shows the World Clock also incorrectly.

If it is possible, please update and use an built-in database of DST usage so people can at least rely on your app for clock, alarm and World clock as they can't rely on their phone anymore.

Thank you so much. Regards.