Cisco CUCM IP Phone Services with CUCM 7 & 8

If you had your Cisco IP phones registered to a CUCM 8.x system and you go back to a 7.x system, you should remember to downgrade the firmware to an appropiate one for 7.x. Otherwise chances are good to end up in problems when trying to access the IP phone services of the CUCM 7.x system.

Problem seems to be that CUCM 7.x tries to address the services via an URL like:
http://172.20.23.210:8080/ccmcip/getservicesmenu.jsp

The phones with the phone load for CUCM 8.x still tries to access the services via:
https://172.20.23.210:8443/ccmcip/getservicesmenu.jsp

So, the only thing you will see, while trying to open the corporate directory, is a "Requesting..." which finaly will end in a "Host not found" message. A factory reset would be the easiest way to go back to the right phone load. Just keep that in mind ....