Can a client of Orbix 3.3 SP12 able to communicate to server of Orbix 3.3 SP7
Yes, an Orbix 3.3.12 based client is able to communicate with an Orbix 3.3.7 based server.
Please also see the "Interoperability with Other Products" section in the Orbix 3.3.12 Release Notes below:
Product Family: CORBA Middleware
Product: Orbix 3
Release: 3.3 SP 12