At BUILD 2013 last week, Microsoft released the Windows 8.1 Preview, Visual Studio 2013 Preview, and the Windows SDK for Windows 8.1 Preview (included in the VS 2013 Preview).
As with the Windows 8.0 SDK, the Windows 8.1 SDK is where you’ll find Direct3D 11.2, Direct2D 1.2, DXGI 1.3, DirectXMath 3.05, a new HLSL complier (#47), and some updates to WIC.
Note that there is no D3D_FEATURE_LEVEL_11_2 hardware feature level defined as of yet. New hardware features exposed by DirectX 11.2 are optional.
The 18.0 C++ compiler in the Visual Studio 2013 Preview includes support for a new __vectorcall x86 and x64 calling-convention, and DirectXMath 3.05 has been updated to take advantage of it. I refreshed XDSP and SHmath to integrate smoothly with this new version. The 18.0 C++ compiler supports additional C++11 and Standard Library/STL/C99 Library features as well. See the Visual C++ Team blog, Somasegar’s blog, and the Visual Studio blog. Remote Debugging Tools packages are also available.
You’ll find VS 2013 Preview projects for DirectXTex and DirectXTK on their respective Codeplex sites. There is a Windows Store app for Windows 8.1 Preview version of DirectXTK Simple Sample available on MSDN Code Gallery.
For developers and publishers of Windows Desktop PC games, be sure to review the Desktop Games on Windows 8.x recommendations, the latest Windows and Windows Server compatibility cookbook, and pay particular attention to the new appcompat behavior of the GetVersion(Ex) API—which you aren’t using, right?
_WIN32_WINNT: When building an application that is 'down-level' using headers in the Windows 8.1 SDK, be sure to explicitly select the correct 'minimum' _WIN32_WINNT value. VS 2013 Preview and the Windows 8.1 SDK default to 0x0603. For Windows 8 compatibility, use 0x0602; for Windows 7 use 0x0601; and for Windows Vista use 0x0600. Typically this is done as part of the project configuration via Preprocessor Definitions. See Using the Windows Headers for more information.
Developer Runtime: The Windows 8.1 SDK (also included with Visual Studio 2013 Preview) is where you obtain the latest Developer Runtime that is compatible with the Windows 8.1 Preview.
Windows Store app developers: Be sure to review the Migration Guide and how to Retarget to Windows 8.1 Preview.
System requirements: The Windows 8.1 Preview will run on the majority of hardware that can run Windows 8. The 64-bit version does require CPU support for some additional instructions which are not present on early first-generation 64-bit processors. See the Windows 8.1 Preview FAQ for details.
The Visual Studio 2013 Preview can be installed on Windows 8.1, Windows 8, and Windows 7 Service Pack 1. For Windows 7 SP1, installing KB 2670838 is required as part of the setup.
Related:Where is the DirectX SDK?,DirectX SDKs of a certain age