I would have never thought this was possible; but the director and creator confirms, it's underway.
http://laughingsquid.com/it-crowd-creator-graham-linehan-bringing-the-geeky-british-sitcom-back-for-one-last-episode/
http://laughingsquid.com/it-crowd-creator-graham-linehan-bringing-the-geeky-british-sitcom-back-for-one-last-episode/
Great news for fans of the series.During a Q&A session at the German re:publica digital conference, IT Crowd creator and writer Graham Linehan announced that he is bringing the award-winning geeky British sitcom and cast members (Chris O’Dowd, Richard Ayoade, Katherine Parkinson and Matt Berry) back to Channel 4 for one last special forty-minute episode. According to Bleeding Cool, this final episode is to be filmed in three weeks time. The script for the special was written over a year ago, but due to a pregnancy and the actors being busy in other TV and film projects, it was postponed. Haven’t seen IT Crowd or need to catch up? All four seasons are available to watch via Netflix, Hulu and Channel 4.