Steven Moffat, lead writer for Doctor Who since 2010, announced to the BBC today that he will step down from his role sometime next year. He will be replaced in early 2018 by Broadchurch writer Chris Chinball. Moffat's final 10 part series will air in spring 2017.
"My timey-wimey is running out. But I am beyond delighted that one of the true stars of British Television drama will be taking the Time Lord even further into the future." -Moffat
Source: BBC