My version is running on an Odroid-XU4. Update refer to armhf. In April I received an announcement about end of support for 18.04, but could not upgrade. Today, when I try do-release-upgrade I get a message that there is no new LTS available.
My second hardware of same type still was on 16.04. I could do a release-upgrade to 18.04. After upgrade and reboot I immediately got a message about a new version and now the upgrade to 20.04 is running.
Why is there no upgrade available for the machine I mentioned first?
Would it help to modify upgrade to take non-LTS versions and switch back when 20.04 is reached?
The machine is used a a backup-server (retreiving the backups of all my running computers) and I want to avoid setting up all from scratch by running a fresh installation with 20.04LTS.
Ubuntu-MATE 21.04 will reach EOL next month so it's the next non-LTS to reach EOL.
No non-LTS releases are supported before 21.04, and the release-upgrade tools will not let you upgrade to a unsupported release (so changing a 16.04/18.04 system to use non-LTS achieves nothing; it'll currently only impact upgrades from 20.04).