ZCM 10.3 > ZCM 11 and Database change

I have a customer who currently has ZCM 10.3.x running with an Oracle backend. We want to move to 11, but with a MSSQL backend. It looks like a migration is not supported (as ZCM10 not on the supported list to migrate). Additionally, there is no Oracle > Internal SyBase > MSSQL or Oracle > MSSQL migration path.

What is the best method to upgrade and change DB, or is it a case of starting from scratch with 11?