Most people speak of the changes in the Fleet Books as FT 2.5.
Much of the XD, Hugh's blessing, has been incorporated into the Project Continuum, which is probably on fast track for FT 3. Nothing for sure, but Jon has been making comments about a 3rd edition released in 2016.
PC is still in shake down, so look at and make comments. I caught an issue that was kept from XD, and I gather there's major discussion of same.
When I can get a game, I've been Real Life'd into not playing much of anything, I mostly do 2.5, with occasional twiddling, but I'm a curmudgeon. ;->=
It's still my favorite space game, and I'm a vacchead at heart.
Doug
Edit: Of course, the fleet books also introduced an alternate movement system, referred to as 'Vector'. Not what I'd call 2.5, but some people love it.