Comment 7 for bug 1924604

I followed the described test case and received the following dialog after running 'do-release-upgrade -p' on an Ubuntu 18.04 system with universe disabled and python2 packages installed.

universe component not enabled

You have the package python-minimal installed which is a python2
package. python2 has been deprecated in Ubuntu 20.04 LTS and is now
available from the universe component of the Ubuntu archive. To
ensure any existing third party code you have installed continues to
work the release upgrade process would install python-is-python2 for
you. However, the universe component of the archive is not enabled on
this system. For the upgrade process to proceed you should either
enable the universe component in /etc/apt/sources.list or remove
python-minimal, libpython-stdlib

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
=== Command detached from window (Fri Jul 2 10:22:36 2021) ===
=== Command terminated with exit status 1 (Fri Jul 2 10:22:46 2021) ===