I am wondering if it is possible to have Unified Message Subscribers and Unity Inbox Subscribers on the same server? We have a single Unity 4.2 server setup for Unified Messaging. That works fine for users that have an Exchange account. We have a number of users that do not have an Exchange email account but still require voicemail. Can I license both on the same server or do I need a separate server, maybe CUE, for my users that have no email account?
Have a look at this thread and the answer from Christopher @ Cisco. He indicates that the 1500 user requirement has now been removed and is no longer applicable :)
Hope this helps!