Hi Bill,
As far as I'm aware, Prepar3D seems to be using a new multiplayer system that's different from all of the Microsoft versions, so I think FSHostClient is still required to be able to connect it to FSHost. Is that not the case?
FSHostClient 1.1 actually worked fairly well with P3D, but it had some problems dealing with aircraft it didn't know about, and the feature where you can right-click a player's name to change which aircraft you see them in. Version 1.2 should take care of all that, and display the list of aircraft correctly depending on whether you're using FSX or P3D. It also has a new entry in the planes.txt file for dealing with the default aircraft displayed (when you don't have the other person's plane) for both FSX and P3D.
BTW, is there any technical info available on P3D's new multiplayer system? Just curious...
Thanks,
Russell