Not the OP, but for example, the United States switched the day to start observing DST a few years ago. Individual states change their observation of DST from time to time.
If you have an event scheduled for next year, and the rules change, do you need to modify the display of that event? How do you know which appointments on the calendar have been updated to follow the new rules?
You have version 1 of your software, then the rules change, so you release version 2. That updates dates on first launch. You have an unrelated bug, and release version 3. what happens to users that upgrade from 1 to 3?
Time handling has a bunch of funny edge cases anyway, even without DST. Those projects often end in tears.
If you have an event scheduled for next year, and the rules change, do you need to modify the display of that event? How do you know which appointments on the calendar have been updated to follow the new rules?
You have version 1 of your software, then the rules change, so you release version 2. That updates dates on first launch. You have an unrelated bug, and release version 3. what happens to users that upgrade from 1 to 3?
Time handling has a bunch of funny edge cases anyway, even without DST. Those projects often end in tears.