The question best matching my situation is described here:
do-release-upgrade failing on Ubuntu 16.04 LTS - says: No new release found
... and questions linked therein; I'd have replied to one of those as an "alternative answer", but my SE rep is insufficient.
In rare cases, the issue stems from a TLS termination proxy being used, a fact that may be obscured from a particular VPS sysadmin, or out of reach to configure.
The issue manifests as follows:
% do-release-upgrade -c
Checking for a new Ubuntu release
Failed to connect to https://changelogs.ubuntu.com/meta-release-lts. Check your Internet connection or proxy settings
There is no development version of an LTS available.
To upgrade to the latest non-LTS develoment release
set Prompt=normal in /etc/update-manager/release-upgrades.
However, retrieving the file manually works, e.g. on Ubuntu 18.04.5 LTS:
% curl -s https://changelogs.ubuntu.com/meta-release-lts | grep -A10 focal
Dist: focal
Name: Focal Fossa
Version: 20.04.2 LTS
Date: Thu, 23 April 2020 20:04:00 UTC
Supported: 1
Description: This is the 20.04.2 LTS release
Release-File: http://archive.ubuntu.com/ubuntu/dists/focal-updates/Release
ReleaseNotes: http://archive.ubuntu.com/ubuntu/dists/focal-updates/main/dist-upgrader-all/current/ReleaseAnnouncement
ReleaseNotesHtml: http://archive.ubuntu.com/ubuntu/dists/focal-updates/main/dist-upgrader-all/current/ReleaseAnnouncement.html
UpgradeTool: http://archive.ubuntu.com/ubuntu/dists/focal-updates/main/dist-upgrader-all/current/focal.tar.gz
UpgradeToolSignature: http://archive.ubuntu.com/ubuntu/dists/focal-updates/main/dist-upgrader-all/current/focal.tar.gz.gpg
do-release-upgrade
is written in Python using urllib
, its urlopen
is tripping up for some reason, and I can't determine why.