CME Upgrade

Step 1- Check the CME/IOS Compatibility Matrix

Here is the CME/IOS Compatibility Matrix Doc

http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/requirements/guide/33matrix.htm

If you have CUE check the following matrix as well

http://www.cisco.com/en/US/docs/voice_ip_comm/unity_exp/compatibility/cuecomp.htm
Step 2- Cisco CME is IOS based feature , hence once we upload new IOS to router , CME version automatically would change

> show telephony-service

Enter the above command to see the CME ver

To load new firm ware files, check this

http://shaijal-allipra.blogspot.in/2011/09/cme-phone-firmware-load.html