I cannot upgrade from 18.04.4 LTS to 20.04 LTS, or indeed any later version. When I run update-manager from the GUI, it tells me the software's all up-to-date. When I run it from terminal, I get:
Failed to connect to https://changelogs.ubuntu.com/meta-release. Check your Internet connection or proxy settings
Per other dialogues here, I removed /var/lib/ubuntu-release-upgrader/release-upgrade-available and then ran
/etc/update-motd.d/91-release-upgrade and /usr/lib/ubuntu-release-upgrader/release-upgrade-motd
But neither solved the problem.
There is no issue with the router, DNS, or whatever, and I can curl https://changelogs.ubuntu.com/meta-release just fine.
To /usr/lib/python3/dist-packages/UpdateManager/Core/MetaRelease.py, I added
import ssl ssl._create_default_https_context = ssl._create_unverified_context
That got rid of the error when I run update-manager, but unfortunately didn’t trigger an upgrade, even though https://changelogs.ubuntu.com/meta-release shows versions through 19.10. And it doesn’t seem like a safe long-term fix.
Apparently, this is a known bug Failed to connect to https://changelogs.ubuntu.com/meta-release-development. Check your Internet connection or proxy settings. It’s labeled fixed on that site, but it is, of course, not fixed for me. The software updater is version 1:18.04.11.12.
A related question is why 20.04 LTS doesn’t show up on https://changelogs.ubuntu.com/meta-release. Because 20.04 LTS isn't listed, I tried Prompt=normal in /etc/update-manager/release-upgrades, in an attempt to upgrade to 18.10, 19.04, or 19.10, but update-manager still doesn’t recognize that an update is available. I just can’t get to any new version of the OS at all. Again, whether Software & Updates is set to prompt for any new release or just LTS releases, I don't get a prompt to upgrade.
This question has been asked many times, but none of the suggested Answers work for me. Is there some kind of update-manager patch available? Or, if not, how can I upgrade? I’d rather not brute-force re-install the OS.
