Microsoft has released Windows 8.1 Update 1 (Spring Update) to manufacturing, according to Mary Jo Foley 's unnamed sources, as well as the known Windows leaker WZor who reports that the RTM build was compiled on February 21 and signed off on February 26. The expected launch date is launch on April 8.
Windows 8.1 Update 1 tweaks include a title bar at the top of Modern/Windows Store apps; new, right-clickable context menus; and the addition of power and search buttons on the Start Screen. Windows 8.1 Update 1 will have a smaller footprint (1 GB of RAM; 16 GB of storage), which will enable device makers to put Windows 8.1 with the update on smaller, cheaper tablets.
With Windows 8.1, the "boot to desktop" will be installed by default on new PCs/devices without touch screens. Users who are upgrading from Windows 8.1 to Windows 8.1 Update 1 who don't have boot to desktop set as their default already won't see their settings change to boot to default, according to WZor.