We are currently upgrading our phone system from call manager 9.1 to 10.5. During this we have discovered that a particular conference phone model (CP-7936) is no longer able to use any soft keys function when the device is off hook (hold\transfer\conference). When the phone is on hook, all the soft keys work (corp directory \ phone book). The phone model works properly once added back to the 9.1 call manager with no unusual configuration (tested with several 7936) and i have compared the 9.1 configuration with our 10.5 to ensure nothing was accidently selected.
Current phone config information:
App Load ID: 7936.3-3-21-0 (shows to be most recent version)
SW Version: 3.3(21.00.0003)
I captured several wire shark traces for them from our 9.1 and 10.5 call managers showing the phone operating properly on the 9.1 and then getting no signals when the soft keys were pushed on the 10.5. They finally sent me an email stating that those phones were not support on the 10.5 and pretty much dropped it. By this point we had sent off for new conference phones so I didn't push the issue. But no, no resolution at this point, good luck.
7936 is EOL/EOS product. It went end of software maintenance back in 2011.
Unfortunately it has never been tested to work with10.X version and no further improvements can be carried out.