Bryan Singer reveals XMFC: DOFP timeline
I thought this might be useful for anyone trying to write within the movie canon timeline.
Bryan Singer:
"I'd say it's not a sequel to one of the others. It's an inbetwequel - that's what I call it, for lack of a better word. It takes place about ten years, give or take, after X-Men: The Last Stand; and in the past it takes place about ten years after X-Men: First Class."
Taken from Bryan Singer Explains X-Men: Days of Future Past Timeline, New Mystique Photo Revealed
Bryan Singer:
"I'd say it's not a sequel to one of the others. It's an inbetwequel - that's what I call it, for lack of a better word. It takes place about ten years, give or take, after X-Men: The Last Stand; and in the past it takes place about ten years after X-Men: First Class."
Taken from Bryan Singer Explains X-Men: Days of Future Past Timeline, New Mystique Photo Revealed