Upgrade from 8.04 to 10.04, "no release found"
86777
Distribution upgrade problem "No new release found"
151584
Why doesn't the command do-release-upgrade doesn't require sudo?
43917
What is the difference between apt-get update and upgrade?
154072
Ubuntu 17.10 doesn't show up in update-manager
56282
16.04 LTS upgrade alert- How to handle it?
64558
What does `do-release-upgrade` really do?
2670
Why is "No new release found" when upgrading from a LTS to the next?
11556
Can I smoothly upgrade from one LTS to next LTS release?
1520
How to install software or upgrade from an old unsupported release?
120713
Release file does not exist
38590
How do I suppress the "New release '12.10' available" message?
4660
Should I be offered the option to upgrade to 18.04.1?
119943
Where can I find a repository for older unsupported releases?
94171
Why Does Software Updater Say No updates Available, but apt-get upgrade Shows updates available?
77705
Unable to upgrade in ubuntu
19288
Update manager doesn't offer an upgrade to the new release
52190
How and when is old-releases.ubuntu.com updated?