I have a mission critical server running on Mate 19.10.
Unfortunately, I forgot to check the support expiration date for that version and now I'm no more able to access Mate's automatic software upgrade features because every time I run the "update-manager" command I always receive the message:
<The repository "http://archive.ubuntu.com/ubuntu eoan Release" does not have a Release file>
Is there an alternative repository to configure on mate to bypass such an annoying problem?
Alternatively, how can I perform the update to 20.04 LTS without re-installing all the software and data present on my server ?
Is it possibile to perform the upgrade offline (by using the .iso install file downloaded from the ubuntu mate site) without losing all the data, information and applications installed on my server ?
Thanks in advance for your support,