Virtualmin makes upgrades and migrations as seamless as possible. The documentation below describes the process of upgrading to a new distribution, as well as migrating to a new server.
Migrations
Migrating To a New Server - How to migrate your Virtual Servers from an existing server to a new server.
Upgrades
On Ubuntu and Debian, it's possible to perform in-place upgrades of your distribution. The following documents describe how to perform those upgrades --
Ubuntu Upgrades
Upgrading Ubuntu 14.04 LTS to 16.04 LTS
Upgrading Ubuntu 12.04 LTS to 14.04 LTS
Upgrading Ubuntu 10.04 LTS to 12.04 LTS
Upgrading Ubuntu 8.04 LTS to 10.04 LTS
Debian Upgrades
Upgrading Debian Wheezy to Jessie
Upgrading Debian Squeeze to Wheezy
Upgrading Debian Lenny to Squeeze
Comments
Is the Upgrade from 16.04 to 18.04 not possible? Thanks :)
Is it supported officially? I tried it a few months ago and had problems with networking issues, Ubuntu dropped /etc/network/interfaces for the netplan setup.
Ubuntu 18 uses the latest PHP which is becoming very important for Wordpress users and other cutting edge software ... as with the latest release from WP now informs on it's Dashboard that PHP -v installed if not 7+ is insecure and needs upgrading. Which is a blatant lie as CentOS backports 5.4 and is fully secure but Wordpress are playing god.
Apparently CentOS 8 might address this but nothing has been said.
Everybody seems to be moving so fast these days that they are shooting each-other in the head, which is not surprising as it's been a free for all for since I do not know when.
Luckily I am retiring soon to a lovely place in France courtesy to my many years of offering a stable dedicated service to loyal customers who do not penny pinch.
CentOs has a great EOL as Virtualmin is well aware off, less work ... C8 better come with the latest PHP.
Just a few more years and I am out of here.
Btw, PHP 7.0.27 will cause a WP warning probably by the end of 2019