Board Thread:Spoilers!/@comment-26443838-20161129150246/@comment-4453062-20161129163241

Normally they end filming in December with the 14th episode of the Season, while they begin with the 15th episode at the beginning of January. The exception is last Season, due to filming 508 and 509 at the same time thanks to 509 being an added episode (bringing the total number of episodes up to 23). This lines up with the upcoming filming dates (each ep takes approximately a week and a half). They started filming 613 yesterday, and should finish it by the middle of next week. Then 614 should take the remainder of next week and the full following week. It also makes sense, cause typically they don't liek to take long breaks in the middle of filming an episode. It makes more practical sense to be able to wrap up an episode before the break, while starting up a new episode when they return:

Kat, a well trusted source who attends set, even said that this guess is correct: http://katmtan.tumblr.com/post/153810592812/karen-david-tweeted-today-that-shes-returning-to