Chaps and Chapessies

I've got a little bit of a problem that I'm trying to track down, we're going over to the use of CADS RC in the near future but on a network license. The problem is we have stand alone CAD units and I've heard that they aren't fully compatible which each other, unless they are both network or stand alone? I've tried getting information on this from suppliers but haven't had any success. Does anyone know of this issue, or if its just a load of smoke to encourage the purchase of newer software.