Hi, Does Galera support rolling upgrades between multiple major versions? I will be upgrading my Galera cluster from MariaDB 10.3.34 to 10.6.x. It'd save a lot of time to jump straight from 10.3 to 10.6 instead of upgrading 10.3 -> 10.4 -> 10.5 -> 10.6. The documentation at https://mariadb.com/kb/en/upgrading-from-mariadb-103-to-mariadb-104-with-gal... implies that the MariaDB version is irrelevant, and only the Galera version matters.
Next, make sure that the Galera version numbers are compatible.
If you are upgrading from the most recent MariaDB 10.3 release to MariaDB 10.4, then the versions will be compatible. MariaDB 10.3 uses Galera 3 (i.e. Galera wsrep provider versions 25.3.x), and MariaDB 10.4 uses Galera 4 (i.e. Galera wsrep provider versions 26.4.x). This means that upgrading to MariaDB 10.4 also upgrades the system to Galera 4. However, Galera 3 and Galera 4 should be compatible for the purposes of a rolling upgrade, as long as you are using Galera 26.4.2 or later.
-- With kind regards, William Edwards