John Hurt at the end of “Name of The Doctor” was introduced as “The Doctor”. Dialog indicated that he is an incarnation from some time prior to 11- so based on the filmed regenerations, he’s either a Doctor Zero or 8.5. Anyways, he’s in the past. That’s the important bit.
While 11 does not consider him worthy of the name “The Doctor”, he’s still a regeneration of the same Time Lord. This makes 11 the 12th incarnation.
And between the 12th and final, oh, The Valeyard.
I’ve seen mentions that the 50th involves some use of archival footage. I wonder if there will be use of “Trial of a Time Lord”? In a show based around time travel and at least limited malleability of the past, they don’t technically have to go there to respect continuity, still, Moffatt surely knows that the time of The Valeyard is approaching if he doesn’t do something about it.