Does Plesk Onyx support dist-upgrade?
Plesk Onyx supports dist-upgrade on Debian-based operating systems.
Starting from Plesk 12.5, it is possible to upgrade operating system on Plesk server. The following dist-upgrade paths are supported by Plesk:
Debian 6 to Debian 7
Debian 7 to Debian 8
Debian 8 to Debian 9
Ubuntu 12.04 to Ubuntu 14.04
Ubuntu 14.04 to Ubuntu 16.04
Note: dist-upgrade on RedHat-based operating systems is not supported.