Restore do-release-upgrade Status

I accidentally interrupted an Ubuntu release upgrade, but the system status wasn't restored to the state before upgrading: it uses a sources.list for new release, and the system is not upgraded.

Now my old release Ubuntu is getting package updates from the new release. I suspect something wrong will happen if I use apt-get upgrade to upgrade them. So I decided to restore the sources.list to the state before upgrading.

sudo sed -i 's/focal/jammy/g' /etc/apt/sources.list
sudo apt-get update