No, there were no server-side changes. You need to give me a snippet of your code so I actually know what is going on. Also, you need to give me a few example product keys so I can see what the customers might be doing.
A good rule of thumb is to never disable network adapters. They can be disconnected from the internet, but disabling the network adapters makes them impossible to read. TurboActivate 4.0 will be released soon to solve the problem of customers disabling network adapters.