* In that link, V11 is not the version of Postgres, it's the version of the test. Scroll down to DB Version.
* Lots of versions are tested, but 9.2.1 is the only version I see on the same hardware that the top MariaDB versions are tested against. The others are on much weaker hardware.
* Postgres 9.2.1 is 12 years old.
And I'm seeing versions tested up through 16.3 which was released in May. In fact even 9.2.1 is less than three years old.