Before the upgrade to CUCM 12.0, check the following phone models; if you use any of these deprecated phone models on an older release of Unified Communications Manager
and you upgrade to a Unified Communications Manager release that doesn’t support the phones, the phones
will not work after the upgrade completes. Also, many of the following are not supported in CUCM 11.5 either.
As of Cisco Unified Communications ManagerFirmware Release 12.0, the following phones are not supported:
The legacy phone models are deprecated for the following reasons:
1-Security—since legacy phone models are not updated with critical software fixes, we have limited ability to protect customers when security issues arise.
2-New feature implementation—legacy phone usage slows down the implementation of newer features.
3-Sustaining—no development support or regression testing is currently being done for these older phones.
What will happen?
If you are running any of these phone models, after you upgrade and switch over to the new release, registration will be blocked on the phone. If the phone remains powered on, the phone will make repeated registration attempts, which will create unnecessary network traffic and a load on the Cisco CallManager service.