I just upgraded to Sage7.3 and seem to have lost access to my old worksheets, which were implemented before the change to Jupytern notebooks. I choose "try to upgrade" when asked, and now get a "can't connect to server" error by Safari when I launch sage.app, saying Safari can't connect to server "localhost". I checked out the old worksheets before after the upgrade to Sage7.3 and before relaunching and choosing to try to upgrade my worksheets.
What can be done to regain access? And can I migrate to Jupytern notebooks manually after that somehow, maybe by copying the source code?
