Migrating from MariaDB to PostgreSQL DB

Focalboard / MatterMost boards in the latest version refuses to migrate the DB schema in MariaDB and therefore refuses to run.

This feels like quite a big deal, at least to us. I know MariaDb isn’t “supported” but it’s used widely in the field. Is this an official departure and changes Maria from “unsupported” to “will not work with” for all users?