To mark the one-year anniversary of the Kinect launch, Microsoft is releasing version 2 of the Kinect for Windows beta SDK. The main changes to this SDK is a 20 percent increase in speed; skeletal and joint tracking accuracy is also substantially improved — this improved tracking system should help developers create more responsive apps.
Microsoft announced these changes on its new official developers blog, which launched along with the new beta and an official Kinect for WIndows website. This update should bring us closer to the launch of Kinect for Windows' commercial SDK, which Microsoft reiterated would be available this spring.
Update: As ZDNet points out, the beta also adds support for the Windows 8 Developer preview.