We’re already nearly at the halfway point on series 9 filming, with the teaser released this afternoon by the official BBC Doctor Who Twitter page. Read-throughs have begun on episode 5, marking the beginning of block three of series nine. Not much is known about episode five at this point. You can see the embedded tweet below, with a larger version of the thumbnail picture.
The new series is expected to begin in autumn of this year.
— Doctor Who Official (@bbcdoctorwho) March 19, 2015