As has become tradition for as long as I can remember, Apple will be giving the hard working App Store approval time some time off for the upcoming Christmas holiday by shutting down submissions and releases between the dates of December 23rd and December 27th Pacific Time. Apple sent out a note through their Developer portal urging developers to make sure their apps are "up-to-date and ready for the winter holidays."
This means that no new apps or app updates will be accepted during that time, so developers will need to make sure anything they have planned for Christmas time is submitted, approved, and scheduled for release before the 23rd. You can also schedule things for after the 27th, but it might get a bit hairy with approval times given the days off the approval team will have. You hear that Binding of Isaac"" I hope you make it out before the shutdown!