[cisco-voip] Forwarding difference after CUCM4 to 8 upgrade

[Rab]

Hi,

Can anyone tell me if there is a fundamental difference in the way CM4 and CUCM8 forwards calls?

We have a cmr with a recently upgraded CUCM8 that has a number of hunt pilots that forward to a CallXpress voicemail server upon no answer. 

This setup is no longer working following the upgrade. Looking at the CallXpress logs the incoming call looks like a forwarded call from the IP phone that calls into the hunt pilot. 

I suspect we need to change a service parameter to retain/replace the forwarding number ANI but it would also be useful to understand any differences between versions. Any pointers would be really appreciated.

Thanks