Hi JB,
The client can download the newer IPC version with their existing licenses
Just make sure that they are configured in CUCM before the migration so that the
proper amount of DLU's is created for each IPC
Cisco Unified IP Phone 7911G, 7912, 7937
Cisco IP Communicator
Cisco Unified Personal Communicator
3 -DLU's
Cheers!
Rob