Longtime Doctor Who showrunner Steven Moffat is stepping down, according to a report from Radio Times later confirmed by the official Doctor Who Twitter account. Taking his place will be Broadchurch creator Chris Chibnall. Moffat's final season, the tenth for the Doctor Who revival, will air in Spring 2017, with Chibnall starting in 2018. Besides a Christmas special, there will reportedly be no new Doctor Who episodes this year.
Moffat is the second showrunner for the revived Doctor Who, having taken over for Russell T. Davies in 2010 at the same time Matt Smith took over as the Eleventh Doctor. Moffat also wrote several key episodes during Davies' tenure, including "Blink" and "Silence in the Library" (an episodes that set up many plot lines that continued through Moffat's era).
Chibnall, who is currently working a new season of Broadchurch (which stars Tenth Doctor David Tennant), has previously written several Doctor Who episodes; he also served as a head writer for Who spinoff Torchwood.
As for the many, many other questions — will Peter Capaldi stick around as the Doctor? What does this mean, if anything, for Moffat's other major show Sherlock? And what's John Barrowman up to, anyway? — there's been no word.