Comment 16 for bug 1875025

That's interesting, thank you for your reply. I think that adding the light-locker package to the Conflicts: field of xfce4-session package in Ubuntu 20.04 would fix this. On the other hand, it seems a bit too strict - one may want to use light-locker instead of xscreensaver and this would make that impossible AFAIK. Alternatively the upgrade script could be improved so that the light-locker package gets removed during the upgrade.