there is a ZCM-Environment with 3 ZCM11.4.3-Appliances (All primary
servers) and one dedicated SLES11SP4 with the SybaseSQL Database.

What is the moment to upgrade the DB-Engine (as described in

Should I do this before start the migration of the first primary Server?
Or can ZCM17 use the old DB-Engine? (Until all ZCM-Servers are migrated)
Can I use ZCM11.4.3 (until I proceed with the ZCM-upgrade) with the new
Sybase-DB Engine?