Conflicting documentation for IM&Presence 9 indicates that cuploging can not be use on IM&Presence 9 but other info indicates that it can be used because jabber will use that record.
On lab production/ lab environment jabber was able to use that record and able to login on the proper IM server. Also on jabber flowchart cuplogin is used for server discovery.
Any ideas why all that confusing information?
It all depends on which mode you are deploying cups: legacy mode or UDS mode. If you deploy in legacy mode then jabber uses _cuplogin
Nb: in legacy mode you will have to define b your tftp servers in I'm and p server unlike in uds where they are auto discovered.