It seems that Microsoft have mistakenly announced the Battlefield 4 release date. The only confirmed news that was announced was that the game has been confirmed.
Microsoft probably by mistake mentioned the Battlefield 4 release date on their official blog, Battlefield 4 will arrive on the Xbox 360 on October 29, 2013.
Battlefield 4 Release Date: 29th October, 2013.
This date was probably chosen for the release of Battlefield 4 because Assassin’s Creed IV: Black Flag is also releasing on the same date on Xbox 360, PS3, PC and Wii U.