A company representative told IGN that the social networking apps are being "retired" as part of a "streamlining" strategy.
Reports that Microsoft was pulling the Facebook and Twitter apps surfaced earlier this week, with sources speculating that the platform holder is implementing the move to encourage Internet Explorer usage on the console.
The latest dashboard update is gradually being rolled out ahead of its global distribution on October 23.
The firmware refreshes the 'Metro' branded interface with a tweaked layout of tiles, combines the TV and Movies channels, and in the US, introduces a sports channel.
Internet Explorer will be added for Xbox Live Gold subscribers, allowing users to browse the web with a controller or Kinect.
Other features include the introduction of the newly rebranded Xbox Video service and Xbox Music, as well as improved search functionality and content management options.
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Copyright: Microsoft Games