Start Date/Time: 12/10/2013 02:55 AM UTC
Service(s)/Tool(s) Affected: CAP/ASD
Affected Locations: Global (Germany and US specific impacts called out)
Instructions for Support Reps: All agents should be aware of the details surrounding the December 2013 Xbox 360 System Update. (See Vendor Communication here with screenshots and specific impact details for German and US customers.)

Summary:
Starting December 12, 2013, Xbox 360 users around the world will be prompted for a mandatory Xbox 360 System Update. This update is part of our continued effort to provide the best possible Xbox Live experience. Customers will be able to download and install the update directly from their Xbox 360 console or offline. [ Register or Signin to view external links. ]
Last Updated
: 12/10/2013 02:55 AM UTC
Last Updated By: REDMOND\vickip
Created By: REDMOND\vickip

Impact NOTES:
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Source: Have insider that works for MS