engine
The database engine to use for the new instance.
This setting doesn't apply to RDS Custom.
Default: The same as source
Constraint: Must be compatible with the engine of the source. For example, you can restore a MariaDB 10.1 DB instance from a MySQL 5.6 snapshot.
Valid Values:
db2-ae
db2-se
mariadb
mysql
oracle-ee
oracle-ee-cdb
oracle-se2
oracle-se2-cdb
postgres
sqlserver-ee
sqlserver-se
sqlserver-ex
sqlserver-web