They need to be updated anyway, and always have been: somewhere in the world, someone changes time rules basically every year, or even every few months. All cur

They need to be updated anyway, and always have been: somewhere in the world, someone changes time rules basically every year, or even every few months. All current OSes already have support for stating "locale X will not use daylight savings / will always use daylight saving, starting from day yyyymmdd at hhmm" through simple updates.