We will update mariadb to the latest version 10.1.38.

mariadb-server/stable 10.1.38-0+deb9u1 all [upgradable from: 10.1.37-0+deb9u1]
mariadb-server-10.1/stable 10.1.38-0+deb9u1 amd64 [upgradable from: 10.1.37-0+deb9u1]
mariadb-server-core-10.1/stable 10.1.38-0+deb9u1 amd64 [upgradable from: 10.1.37-0+deb9u1]

Start maintenance window: 29/04/2019 23:00 CEST
Stop maintenance window: 30/04/2019 01:00 CEST