I just tried to run an update and got this message from the app center:
I've tried reading around but all the potential answers I've found go over my head. I'm not really sure what I'm doing re: messing with repositories. Does it seem like a line has somehow been changed in sources.list? What should be there?
UPDATE:
Upon suggestion, I tried
sudo ppa-purge ppa:versable/elementary-update
And I got:
W: The repository 'http://ppa.launchpad.net/versable/elementary-update/ubuntu xenial Release' does not have a Release file.
E: Failed to fetch http://ppa.launchpad.net/versable/elementary-update/ubuntu/dists/xenial/main/binary-amd64/Packages
404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
Warning: apt-get update failed for some reason
Thanks for any help.