Hi,
As of now the latest available builds ( till 9314 ) will work in MySql. We will be removing the support within 2 months. The ppm when applied will check for the database and if it is MySql will stop the process. So customer's will be able to run the old build in Mysql itself. But if they want to come to the latest build, they need to move to Postgres / MSSQL and then do the upgrade.
Thanks
Shanmugam PL