Just noticed this error message a) still refers to MySQL and b) refers to the database with a masculine pronoun. I assume a 20 year old translation error is involved; the error in English should read "...and has its hostname changed..." I couldn't find an appropriate UI component so am filing this under Replication.

Neither --relay-log nor --relay-log-index were used; so replication may break when this MySQL server acts as a slave and has his hostname changed!! Please use '--log-basename=#' or '--relay-log=mariadb-relay-bin' to avoid this problem.