This Sunday will be the first opportunity for the GPS clock to experience a DST change. I've tested it offline and it seems to work ok, but hopefully that will translate to correct behavior in anger.

If it fails utterly, then the obvious workaround is to disable DST and manually fiddle with the timezone hour menu, but rest assured, there will be fixes forthcoming if it doesn't work perfectly.

If it works in the U.S., then I have good confidence that the other supported rule sets will work. We'll still have to watch the first transition back in November to get full confidence, but hopefully it will all just work as designed.

EDIT:

I cheated a bit and advanced the timezone this morning while maintaining US DST rules. This let me see the transition early, and it was correct.