Sim, Moffat está deixando Doctor Who no final de 2017.
De este artigo lançado oficialmente pela própria BBC:
The head writer and executive producer of Doctor Who, Steven Moffat, is to step down from the show, the BBC has confirmed.
His last series will go out in spring 2017 following a Christmas special, after which he will be replaced by Broadchurch writer Chris Chibnall.
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"At the start of season 11, Chris Chibnall will become the new showrunner of Doctor Who. And I will be thrown in a skip."
Este artigo do Cinema Blend confirma que Moffat ficará para o especial de Natal de 2017, bem como para a série 10 anterior:
Steven Moffat has been the showrunner on Doctor Who since 2010, but the long-running series is about to go through a slew of changes. Not only is current lead Peter Capaldi getting a brand new companion in Pearl Mackie during Season 10, but Steven Moffat is also preparing to step down as the showrunner on the series. Now, we finally know when the changeover is going to take place, but it looks as if it won’t happen for a while, yet. Steven Moffat just confirmed he will not be stepping down as soon as Season 10 ends. Instead, he will stick around for the Christmas special in 2017, as well.