I upgrade a server from 16.04 to 18.04.
After the final reboot, I re-activated the additional source list which have been disable during the update. (It was Zabbix repository)
Then I upgrade the system, but did not notify about new upgrade.
However the version installed was for xenial and a version for bionic is available to work properly. (same version).
When I tried to :
update : no new version available
reinstall : unable to locate package (seems logic because I replace xenial by bionic)
Manually install the bionic version : The system consider the current version (xenial) the latest
I finally remove and install the packages.
But I would like to know what is the proper way to upgrade package from a Ubuntu version to another and avoid this ?