I can't see where the opening post was asking comm questions, but thanks for pointing that out nevertheless Koi. To complete your statement, let me say that no IL-2 version ever had a working ingame voice chat. The provisional code is there, but apparently it never worked.
would you say UP3 is the next logical step for online play if moving on from HSFX?
Yes and no.
It's two completely different pair of shoes.
HSFX is IL-2 1946 4.12.2m + SEOW. It's a special version made for and by a special squad (242 Sqn) who liked to play a special fashion of the game (Scorched Earth Online War, "SEOW", a persistent coop campaign system).
Since HSFX included a certain set of mod planes and it was tested for online compatibility, it grew famous among online IL-2 1946 players.
Unfortunately, HSFX always contained a set of bugs and glitches, most notably maybe the "spawn bug" (you spawn above enemy territory instead on your homebase, exisits since HSFX 6), which have never been addressed successfully and, most important, HSFX development has ceased long time since and the whole 242 Sqn website which once hosted HSFX development is gone these days.
UP3 is IL-2 1946 4.10.1m + Full featured Zuti MDS + Nearly every mod available at that time.
The UP3 Patch Pack Series added a couple of features on top, e.g. IL-2 4.13.4 AI code, ordnance view, weapon release mod switch, fully tested online replication etc. - all of these improved a lot over official IL-2 1946 standards, even compared to 4.13.4m.
This is the most sophisticated online compatible pack available these days.
And not to forget it's the only pack featuring the full size version of Zuti's Moving Dogfight Server "MDS" with resources management, repair/refuel/rearm and much more.
And Jets (subsonic that is).
And Missiles (early ones).
And so much more.
A small set of very special features from later base game versions has not been ported so far, e.g. some AI commands like "guard area" are not in yet and "taxi to takeoff" is missing as well, so if you are one of the two persons on earth using such feature, you will have to wait for it to be carried over to UP3.
Cheers!
Mike