In the anniversary year it was revealed that Matt Smith was the 13th and final incarnation.
John Hurt was introduced as the War Doctor, the forgotten 9th incarnation. Bumping up the numbers David Tennant took the 11th and 12th incarnations having regenerated in The Stolen Earth/Journey’s End. This made Matt Smith the 13th incarnation.
The Doctor was granted a new regeneration cycle from the Time Lords in The Time of the Doctor allowing the Doctor to regenerate again.