Microsoft has officially announced at /Build/ changes coming the to Windows 8.1 platform. Changes announced include:

The ability to choose to boot directly into Desktop mode or directly to the start screen Home screen tiles can now be resized into 4 sizes. The smallest tile is 1/16 of our current standard tile in size, and it can’t be animated (similar to Windows Phone). Read list, located in your charm bar, operates like a clipboard storing links and pages to read later on different devices. Panorama, powered by Photosynth technology, is now the default camera app. Smart Search provides universal search, presenting everything the OS is connected to including local files, internet pictures, websites, Wikipedia entries, etc. Xbox Music and browser will now recognize playlists fused into web pages, and play the list in Xbox Music. Additional language support now covering 139 languages. Deeper SkyDrive integration allowing you to check your SkyDrive usage via your PC settings. The lock screen is now able to play a series of pictures like a slideshow from the feed provided locally or via files in your SkyDrive. Skype calls can now be answered right on the lock screen. Animated background now supported for your Modern home screen. Sliding from the bottom up on your Start scree allows you to access your “all apps” screen showing all apps loaded on you device. New features added for picture editing, including effect filters via the included pictures app. Added support for 3D printers. Return of the Start button on the desktop screen combining the Modern UI with the traditional desktop. Mail app improvements including a new group for key contact, a new newsletter category for organizing your inbox and the ability to open a picture attachment in an email will now show it in a snapped view. Modern version of PowerPoint was demoed but still in beta stage. Windows Store purchased apps can now be automatically updated without user interference. Acer W3 announced with a 8″ screen which will begin a whole series of small-sized devices.

Further details to be made available as they release. The preview is also available and can be downloaded here:

Download the Windows 8.1 Preview