User blog comment:Longlivemerlin/The Kindness of Strangers: Who was that? and dialogue teasers/@comment-5815946-20121202034213

Well, seeing as there are only four more episodes left of the entire series, I'm certain they'll do magic reveal in the last episode. So I wouldn't be surprised if Morgana finds out Merlin is Emrys soon. But - knowing the writers, more likely is that Morgana will get very close to finding out, but will not actually find out until episode 11 or later.