I've switched all of our installer links to point to the new Virtualmin 6.0 installer. It's been in beta for a couple of weeks, and has been pretty extensively tested on all of our supported distros...but, it's almost entirely new code (the first major overhaul of the install system in over a decade), so it's likely got more quirks that we haven't found yet. Please tell us when you find them.
We always recommend using the latest supported version of your preferred distribution, but that's even more true now. The most recent versions of CentOS, Debian, and Ubuntu, are simply a better experience. Because they all use systemd, the install is more consistent across them. They all get php7 packages during installation. They all get a firewalld firewall configured specifically for Virtualmin and they get a fail2ban configuration to suit, as well. So, there are lots of good reasons to use CentOS 7, Debian 9, or Ubuntu 16.04 LTS (rather than earlier versions of those distributions).
And, just a reminder: The installer is not for upgrading a production system; once installed, you should never run the install script again. I'll provide a script to switch repos in the next day or so, for folks who want to migrate to the new repository and get access to the new
virtualmin config-system command, among other things.
Documentation is still being updated, but the Download page and the automated installation docs are currently up to date. The manual installation docs aren't updated yet, and that's where most of the interesting changes have happened.
So, this is a "soft launch" of Virtualmin 6. We consider the new installer better and more reliable than the old one, in addition to having a bunch of new features setup by default, so it was worth getting it out there even before we cover all of the new features in detail in the docs. The default mode (just running it with
sh install.sh) will result in the same basic stack as the old installer (LAMP, plus a mail stack with ClamAV/SpamAssassin), and that needs no additional docs.