When Google first started to roll out Android 4.2 Jelly Bean two weeks ago a very minor, but rather serious object was excluded. Android 4.2 had no memory of what December, and Christmas, was. While the month of December was still included in the Calendar app, it was omitted from the People app and could not be used to set birthdays or anniversaries.
Today, the Android 4.2.1 update has started to arrive on Nexus devices, including the Nexus 4, 7 and 10. Other devices have not been effected as very few devices were ever running Android 4.2.
The update appears to bring nothing new to the table except for reinstating the month of December.
KitGuru says: Two weeks is a pretty good turnaround. But regardless this bug should have been picked up in the testing phases.