Simply point your client to cat.casa and go!
Notice: If your client does not support delegation you may use matrix.cat.casa, but keep an eye out for this page and the status page if it suddenly stops working!
Sorry for the long downtime, folks! This upgrade was really important, as version 13 is only supported until November. Further upgrades will not need to take place before 2029.
It took a long time because the database has grown to over 1TB in size. Yes, the database obviously needs to be stopped for the upgrade. For some reason pg_upgradecluster didn't want to make use of my BtrFS.
ordered by importance