It's one of the "older" guesses (I'm not calling them insider information), I have—compiled from all the dark places of the Internet—the following dates left in my calendar. I didn't put the source of the date in it, because it honestly doesn't matter:
December 4-6 (I don't remember where this came from)
December 11 (stemming from the 12/11 (US date) and 11.12. (German format) confusion)