Ubuntu 18.04.1, Gnome Shell 3.28.1, Ubuntu Software 3.28.1, on an x86_64 architecture computer.
Recently I began having this problem:
Ubuntu Software presents desktop notifications saying that various software packages have updates available. I start Ubuntu Software, go to the "Updates" tab, and see all the packages to update with "Update" buttons next to them. For every single one, when I click on the "Update" button, I get an error message of this format:
Unable to update xxxxx: Could not find update for 'xxx/xxx.xxx.xxx.xxx/x86_64/stable'
where "xxx" represents some text.
(I attached a screenshot of a typical message to this posting for a software package called "Cozy".)
After I dismiss this message, the application disappears from the list of packages to update. Eventually, I go through them all, and then Ubuntu Software says "Software is up to date".
I have no idea whether or not the packages actually updated correctly.
What does this message mean, and what should I be doing to fix whatever is wrong?
I encountered a similar problem with Audacity, which I had installed via flatpak. In my case, I did not get an error message more specific than "Unable to update Audacity," and I never got the misleading "Software is up to date" message. It would always fail the same way.
Here's how I resolved it:
flatpak listorg.audacityteam.Audacity/x86_64/stable, the name isorg.audacityteam.Audacityflatpak update NAMEfor each app