Do this to start getting rested XP on your alts

Apparently your previously max-level alts (i.e. current level 50s) only start gaining rested XP once you've logged into them after an expansion launches. It has been like this since TBC.

So even if you don't intend to play your level 50 alts yet, log into each one so that you can start accumulating rested XP in the mean time.

I spotted this somewhere else and others have confirmed it too, thought it would be important to share.

Hope you're all enjoying Shadowlands - I'm only level 53 but enjoying it thoroughly so far