this is a nearly breaking change, but didn't seem up to the level of a major release.
If you're using ai:auth, it was storing access _tokens, and from time to time would error out and have to be reauthed.
It now uses a refresh token process. So it'll be better than that (run once, store for the long-term), but an existing access token will be broken from previous versions even if it's still valid for a while.