Microsoft is all set to officially unveil Windows 9 at a special event on September 30 -- and so we thought it would be a good time to run through everything that we already know about Microsoft's new operating system. Most of these features and changes are reliably sourced from people close to the development of Windows 9 or from leaked builds of the Windows 9 Technical Preview. We'll also update this story with an official list of Windows 9 features when Microsoft starts releasing public beta builds next week. In short, if you want to find out about Windows 9, this is the place to be.