I dont doubt of your answer and indeed i've tried this function in some versions of ccm and its only possible from 4.2.
Do you have any document that shows the inclusion of the functionality from 4.2?
From CM 4.2.1 release notes
Cisco recommends that an assistant use the Cisco IPMA-on-phone features only if that assistant supports no more than five people.
look through CM Admin/Feature and System guides for more info.
Sorry but controling IPMA from the assistant phone without the pc console is possible in 5.x. Been there, done that.
Hope this helps!
I tried IPMA service in the assistant phone [ CUPC] it's won't working.
Assistant Phones subscribed the IPMA service.
whether IPMA-on-phone services only for Manager,or it's depends on device model.
CUCM version 7.1.2 CIPC version 2.1.2