After an Avaya Aura® Communication Manager (CM) upgrade, a customer called Avaya support because their H.323 telephones were unable to login. Support was able to confirm that the telephones had not been upgraded.

Which pre-implementation step was omitted?

A. Insure Presence Services was upgraded correctly.
B. Test all third-party equipment and software.

C. Verify the firmware version installed is compatible with existing versions.

D. Provide accurate licensing specification.