This post is just to answer this question. Is the current version of ISPConfig (3.2) compatible with MySQL 8? on a multiserver setup, can I have different MySQL versions, for example 5.6 and 8.0 on different servers?
ISPConfig is compatible with the version of MySQL or MariaDB that comes with the OS ISPConfig runs on. Ubuntu 22.04 has MySQL 8, so it should be supported, but I think ISPConfig uses MariaDB on Ubuntu 22.04. Yes iff the servers have different operating systems with those versions of MySQL, This forum has threads about upgrading database server on ISPConfig hosts, and my recollection it does not always go well.
I would answer no, it is not really fully compatible (except may be the old server with old OS and old mysql version) and the best is always to use default mariadb that came with the latest OS instead, as it is the one that is mainly supported by ISPConfig, with no problem or very minimal ones, as far as I know. However you can always try it and see how it goes with latest ISPConfig though.
i've experience some of the problems alluded to by @Taleman, having added the official mariadb repo to install the latest version, an update then attempted to install an mariadb update from the ubuntu repo.. removing the mysql binaries and then stopping.. refusing to re-install from either the ubuntu repo, or the official mariadb repo. it took a lot of effort (and swearing) to get the system working again. my advice now... leave it alone.. stick with the standard OS installed releases..
