I tried to update my system this morning, running Ubuntu 22.04 Jammy, and get this message.
The repository 'http://us.archive.ubuntu.com/ubuntu impish-updates Release' no longer has a Release file.
I searched the internet and these pages but can't find out how to get around this warning. It's not a PPA and when I run grep -r -i ppa /etc/apt/ there is nothing that matches the name of the offending repository.
There is also nothing in the Software Updater that matches. I tried switching different main servers, but with no success. This is the first time this has happened and I have been running 22.04 for months now.
Update:
These are the first four lines output by sudo apt-update
Ign:1 http://us.archive.ubuntu.com/ubuntu impish-updates InRelease
Err:2 http://us.archive.ubuntu.com/ubuntu impish-updates Release
404 Not Found [IP: 91.189.91.38 80]
Get:3 https://download.docker.com/linux/ubuntu impish InRelease [48.9 kB]