It's been known that a final 40-minute episode was in the works, bending around the conflicts of a cast who are all very, very busy now. Presumably, this special episode will air in the late summer or fall. I've missed this show, but with a track record like they ended up with, I'd rather it all be good than have a bunch of filler crammed in around the good stuff.
As a bonus, here's the awful US pilot/remake of the show, which is not awful on account of any of the actors: