We currently have a stack of 3750G switches that are running
12.2(46)SE C3750-ADVIPSERVICESK9-M
Our 3750X is currently running 15.0(2)SE C3750E-UNIVERSALK9-M and I believe we were told you can't stack with a Universal IOS image. We have the universal on there because we have some 10GB fiber connections on it that Cisco told us wouldn't work otherwise.
I realize that the switch versions need to match, but the question is, which version should we work off to have use of the 10GB SFP card?