AICN saying 20th Century Fox have registered Days of Future Past with the MPAA.
Days of Future Past was a two-part story that featured an apocalyptic future, run by mutant hunting, killer Sentinels. The giant robots became martial law unto themselves after the fear-inducing mutant assassination of prejudicial presidential campaigner, Senator Kelly.
As Wolverine, Colossus and Storm mount a final assault on the Sentinel base, Shadowcat takes over the body of her present day self, in order to get the X-Men to prevent the Senator's assassination by the Brotherhood of Evil Mutants.
Alternate timelines readjusting, would help in-movie continuity to explain differences between the new X-films and those that came before it.
Adding weight to the story-lines sequel possibilities is the fact Days of Future Past was Mystique's first time heading the Brotherhood, explaining the importance of Jennifer Lawrence's availability outside Hunger Games for the film's production. Definitely to be continued.