Ubuntu 16.04/Online updates
The installed packages can be updated easily in Ubuntu:
If you're doing system backups from the server, a backup is appropriate before upgrading. But many people only make backups of their user data, and install Ubuntu new from scratch if necessary. This is a question of strategy: Backups reduce downtime, but are annoying. In contrast to the user data, the Ubuntu software can always be restored by loading from the network. Then it only must be configured again.
Continued: Recent Mono