In an email sent to iBooks publishers last night, Apple confirmed that iTunes Connect will shut down for a week from December 22 through December 29. While the email has been sent to registered iBooks Store publishers, Apple's annual iTunes Connect holiday shutdown will also affect iOS and OS X developers, who during that time won't be able to access iTunes Connect.
From the email:
From Monday, December 22, through Monday, December 29, 2014, iTunes Connect, iTunes Producer, and iTunes Connect for iOS will be unavailable.
During this time, you will not be able to access iTunes Connect, submit new books or book updates, or make price changes. You can schedule a book release or price changes to take place between December 22 and December 29. Just make sure that your changes are scheduled, submitted, and approved by December 18, to ensure your book remains available during this busy period.
For users, this means that no new apps, updates, or price changes will be available during the week. Developers who wish to release new apps and updates or price changes to apps or In-App Purchases will have to do so before the iTunes Connect shutdown.
Currently, Apple has only shared the 2014 iTunes Connect holiday shutdown dates with iBooks publishers; a developer update should be posted on the company's Developer News page soon.