Existing IP Office systems being upgraded to IP Office Release 11.1 require a software upgrade license.
•! Warning: Upgrade License Requirements
On a new system, when the first call is made, the software level being run is written into the control unit's permanent memory. Any subsequent upgrade to a higher release requires the addition of a Basic Edition Upgrade license for the target release. Systems upgraded without that license display "No license available" on some phones and will not allow any telephony functions.