For those who own Nexus 4, 7 or 10, you must be wondering why Google miss out December in their calendar. Due to this reason, Google release the Android 4.2.1 update to fix this bug. Users can now update to this version via Over-Air-Update (OTA). This is a 1.06 MB update file to fix the one and only one bug, December-missing and no improvement provided.
For those who have rooted their Nexus devices, you can manually flash the update file. For non-rooted devices, you may wait for your turn to receive the official update.