Originally slated for a autumn start date, shooting on Matthew Vaughn's follow up to his X-Men reboot has now been put back to January, primarily to avoid any scheduling conflicts for Jennifer Lawrence. The actress, who is reprising the role of Mystique, is set to start work on The Hunger Games sequel, Catching Fire, in the autumn, so this change frees her up to do both.
No details on plot for the X-Men sequel have been revealed, though script writer Simon Kinberg (X-Men: The Last Stand, This Means War) has said it will be heavily Magneto focused, pleasing fans of Michael Fassbender to no end. The original cast are locked in to return, as well as the originals co-writer Jane Goldman (Stardust, Kick-Ass) who joins Kinberg in crafting the story.
Source: The Hollywood Reporter