MariaDB 10.2.7 and future releases (5.5, 10.0 and 10.1 branches are not affected) just resolve an old bug in SQL standards implementation and introduce a BC break

Ticket that explains changes https://jira.mariadb.org/browse/MDEV-13132
Ticket that confirms (in comments) only >= v10.2.7 are affected https://jira.mariadb.org/browse/MDEV-13341

Concretely, for Doctrine, schema update just gone crazy and want to update every column with NULL default because 'NULL' is return by MariaDB instead of NULL.
I don't find any other issues… for now.

For the moment, MySQL don't have the same issue.