Release upgrade an unsupported version of ubuntu
If you want to do a release upgrade with an unsupported version of ubuntu, it seems to be quite straight forward, but nonetheless, you run into a couple of difficulties, because the sources are moved from
old-releases.ubuntu.com which results in not finding these if you want to do a release-upgrade.
What did the trick for me was to manually set the IP-Adress of the server
old-releases.ubuntu.com in the
/etc/hosts file for
All other suggestions like changing the url in the
/etc/apt/sources.list and modifying the
/etc/update-manager/meta-release file didn't work, because i.e. of wrong checksums and in the end it always tried to contact
archive.ubuntu.com for an updated version of the packages.