TYPO3 Core

After having issues with a DB compare in a 10.4 instance with #93150 and the hint from Christian Kuhn, ich checked the environment status of the system:

The dropdown in the header reports this database version:

MySQL 5.5.5-10.1.47-MariaDB-0+deb9u1

This is unsupported as stated by https://get.typo3.org/version/10#system-requirements - MariaDB needs to be at version 10.2 or 10.3
The environment status however reports, that this version is fine

MySQL version is fine

The version is extracted like this

preg_match('/MySQL ((\d+\.)*(\d+\.)*\d+)/', $connection->getServerVersion(), $match);

So since Debian 9 says the version is MySQL 5.5, there is no error shown.