As expected following the news last week of Matthew Vaughn's exit, Bryan Singer will return to the director's chair on X-Men: Days of Future Past.
He still has Jack the Giant Slayer to wrap in post-production (Assuming that's near complete) and noticeably no word on when production will commence. Filming was aiming for January as means for Fox and Lionsgate to share co-star Jennifer Lawrence. But with the change of directors and the script still written, that’s unlikely despite the studio sticking to its July 18, 2014 release date.
Don't have an idea of who will return; Lawrence, Michael Fassbender and James McAvoy are givens but Singer's role on Days of Future Past, before the director swapping, was to sweet-talk original cast members to return; like Sir Ian McKellen who bolted after his contractually-binding appearance in the Singer-absent X-Men: The Last Stand. Hugh Jackman, Patrick Stewart and Rebecca Romijn returned for directors not-named-Bryan. Nothing wrong there, just pointing that out.
And what of the returning Singer? Being as critical against Peter Jackson and Ridley Scott for "going back to well," that rule applies too. Difference is Singer has an active and bigger than given credit for, role on X-Men: First Class. It helps that Fox learned from their mistake letting him go back in 2004 instead of sharing him with Warner Brothers. We'll see.