I've just completed an (unsupported) upgrade from an eol version to ubuntu 23.10.

The upgrade went fine and there were no errors, the desktop comes up, and everything looks ok.

As I do not get the option to upgrade to 20.04, I 'played around' with the update manager and noticed that when I try to change the update server I get the message

'error while refreshing cache' and pk-client-error-quark

I'd appreciate any suggestions on how to resolve this.