we currently have CUCM 9.02 and CER 9.02, however, CER 9.02 does not support all our switches so we need to upgrade CER to 10.02 which supports CUCM 9.02. The problem is CER uses PLM 10.51. when you go to the release notes for PLM 10.51 it supports CUCM 9.1. so does that mean we need to upgrade CUCM to 9.1 for this solution to work? upgrading CUCM to 10.X is not an option at this point.