Just to add I would like to know this as well, just configuring a epo 4.6 p1 server as we speak, if there is no response might give it a try and report back.
Or any update on 9.2 being released?
I have a epo 4.5p4 with hdlp 9.1 and Endpoint Encryption 6.1.2 and let me know if I can upgrade epo 4.6.1 without compatibility problems.
I have EEPC installed on my new ePO 4.6 and its 6.1.2 so I am guessing thats fine for that. There should be a document on the KB somewhere with what is and inst supported.
Using my grant number just now I see that the HDLP 9.2 folder is now an option so maybe we will find out soon enough, I wont install 9.1.100 as a test if I can install 9.2 through the software manager and make upgrades + my life easier!