M Series is the thirteenth series of QI, featuring topics relating to words that start with "M"; it began airing on BBC Two on 16 October 2015, with the XL edition broadcast a day later. There are 16 episodes, each with XL versions; they were filmed throughout May and June 2015. It was announced in October 2015 that this would be the final series hosted by Stephen Fry, with future episodes being hosted by Sandi Toksvig.