This likely has to do with the deadsnakes PPA you have enabled which provides versions of python packages outside of the official Ubuntu archive. Please remove this PPA using the command 'ppa-purge' from the package of same name and try the upgrade again. Thanks and good luck!
** Changed in: ubuntu-release-upgrader (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1948587 Title: Not able to upgrade to ubuntu 21.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1948587/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs