It was shaping up to be a nasty battle of tug-of-war between 20th Century Fox and Lionsgate, both of whom needed Jennifer Lawrence for big, splashy sequels that were supposed to shoot this fall. Fox wanted her to return as Mystique in the X-Men: First Class sequel, while Lionsgate needs her as Katniss in the Hunger Games sequel, Catching Fire. Seeing as she's committed to both, someone had to budge, and surprisingly it's Fox, who've decided to push their schedule on X-Men back to January to allow Lawrence to film Catching Fire in August-September.
For fans this really is the best move, especially for Fox who came under fire from critics, as well as members of the X-Men: First Class production and cast, for rushing that film's production in order to meet a specific release date. Pushing back the start time should hopefully give them more time to prepare a worthy sequel. Meanwhile, Catching Fire is now under the gun to either work out a deal with Gary Ross (which is currently in limbo) or go elsewhere in search of a different director.
Matthew Vaughn will return to helm the X-Men: First Class sequel, which is expected to bring back its central cast, including Michael Fassbender and James McAvoy. The film currently does not have a release date, though Catching Fire is due in theaters on November 22, 2013.