Production network dbs are mostly upgraded to Debian 10 "Buster" and MariaDB 10.4. Beta/deployment-prep should follow to avoid having a difference between production and testing.
MariaDB 10.1 EOL 17th Oct 2020: https://mariadb.com/wp-content/uploads/2019/07/mariadb-engineering-policies-v2-01_policy_1036.pdf So it is no longer supported.
We need to find an owner of the deployment-prep cluster dbs (Release-Engineering-Team?) and urge them to upgrade them, with our support.