Today 343's very own Frank O'Connor confirmed that Halo 3 will be an Xbox 360 release next fall. Of course, this doesn't mean we won't see a new Xbox in 2012, it just means that Halo 4 wont be a launch title for the new Xbox.
While this would be a first for Microsoft, it could mean that the next major Halo title will not release on its new console, were a new Xbox to launch next fall.
Frank O'Connor confirmed the 360 to be the platform when he stated on NeoGAF that "Halo 4 will be on Xbox 360 and use a modified core of the Halo engine(s)".

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