Will MultiMaster synchronization take place if the Primary and Secondary Administration servers are using different versions?
Directory and Resource Administrator 7.x
Prior to Directory and Resource Administrator (DRA) 7.5, the Administration servers must be using the same version for Multi-Master Synchronization (MMS) to take place. The typical upgrade path is to upgrade the Primary Administration server first and then upgrade the Secondaries. During the time when the Primary is at a higher version then the Secondaries, Security model and other changes will not get replicated to the secondaries.
Beginning with DRA version 7.5, DRA is "backwards compatible", meaning that a DRA 7.5 Primary Administration server will perform a MMS with older DRA 7.x Secondary Administration servers.