[Users] EL 6.3+ nodes and 3.1 compatibility?

With ovirt 3.1 EL 6.3 nodes will only work with a data center set to 3.0 compatibility mode. Is there any reason(s) why EL 6.3+ nodes would not be allowed in a 3.1 compatibility level cluster? This assumes non use of gluster since adding vdsm-gluster to an EL 6 node requires some work package update/version wise (not impossible). - DHC