What if my country splits itself in two, and the location “Oslo/Norway” that used to describe my time zone no longer describes the place I live. And they change the time zone offset to be one hour off from what it used to be for Oslo/Norway but in the place I live the time zone offset remains as it was before the split?
Don't use Oslo/Norway if you're in e.g. Trondheim; store Trondheim/Norway.
I should note that it is not possible to make a database of geolocation->UTC offset that is legal in all countries, since there are countries with disputed borders, some of which care very much that no software imply the "wrong" border.
> If you're worried about the future timestamp being at a specific local time (say 10 AM on a future date), it's actually better to store a naive time and a location than the IANA timezone name.
Europe/Oslo would be the IANA name for mainland Norway (Svalbard and Jan Mayen are in different IANA regions).
If you're meeting somewhere at a specific time, you might as well specify that place really precisely (Maybe: Nidaros Cathedral, Trondheim, Norway) and then use that place to infer the proper UTC offset when the date approaches.
There's no perfect solution as landmarks, names, &c. can all change.
