We almost got excited for a second there. A new version of 360's system software has been released but, according to Major Nelson, adds no new features to the system.
A few minutes ago, the team released a system update for the Xbox 360 over Xbox LIVE. Sometime over the next few hours when you sign in to Xbox LIVE you’ll recieve a prompt to accept this mandatory update. This update contains code to ‘prepare for future growth of the service.’ There are no other changes or enhancements in this update…in other words no new features. The next obvious question you’ll have is about the Spring update. At this point we have nothing to announce, and the moment there is information to share I will do so.
If it doesn't add Dolby 12.6 surround and boost resolution of degraded AVIs to house-size, we're not interested, frankly.