To upgrade Zonemaster-Backend from Zonemaster-Backend versions smaller than 1.0.3 you have to upgrade the database:

MySQL

Run /usr/local/bin/patch_db_mysql_for_backend_DB_version_lower_than_1.0.3.pl

PostgreSQL

Run /usr/local/bin/patch_db_postgresq_for_backend_DB_version_lower_than_1.0.3.pl