I'm pretty sure they already confirmed there will be a full series this year.
EDIT: Yep, here's the article: http://www.radiotimes.com/news/2015...will-be-a-full-series-of-doctor-who-next-year
Unless they begin filming in the next two to three weeks, we won't see all of that "full series of 12 episodes, plus a Christmas special" in 2016. And there's no indication that they're ready to do any such thing.