This should be closed. I found out that I had packages from a ppa repository which were duplicates of standard ubuntu packages. So this bug report should not even been submited.
Useful commands to solve this problem were: for name in `dpkg -l | gawk -e '{print $2}'` ; do apt-cache policy $name; done | grep ppa ppa-purge ppa:ubuntugis -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1901338 Title: upgrade to latest stable release fails To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1901338/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs