Comment by deryilz

As another commenter said, sometimes upgrades require manual intervention. You can fix this using a tool like informant which shows you all the interventions you have to do before you upgrade.

Also, you can use a tool like snapper + btrfs-assistant (both of which come pre-installed on Cachy IIRC) which lets you fully revert your filesystem (snapper rollback) or partially (snapper undochange) if something breaks. Just make sure to use a btrfs filesystem for that.