Microsoft has released a new Windows 10 Preview Build of the SDK and the Mobile Emulator to be used in conjunction with Windows 10 Insider Preview (Build 16267 or greater).

The Preview SDK and Mobile Emulator can be downloaded from developer section on Windows Insider.

For feedback and updates to the known issues, please see the developer forum. For new developer feature requests, head over to our Windows Platform UserVoice.

Things to note:

This build works in conjunction with previously released SDKs and Visual Studio 2017. You can install this SDK and still continue to submit your apps that target Windows 10 Creators build or earlier to the Windows Store.
The Windows SDK will now formally only be supported by Visual Studio 2017 and greater. You can download the Visual Studio 2017 here.
Known Issues

Compilation fails on non-Windows 10 platforms
When building apps on previous platforms, you may get a build error:
C:\program files (x86)\Windows Kits\10\bin\10.0.16232.0\x86\genxbf.dll:C:\program files (x860\Windows Kits\10\bin\10.0.16232.0\x86\genxbf.dll(0,0): Error WMC0621: Cannot resolve ‘GenXbf.dll’ under path ‘C:\program files (x860\Windows Kits\10\bin\10.0.16232.0\x86\genxbf.dll’. Please install the latest version of the Windows 10 Software Development Kit.
Process ‘msbuild.exe’ exited with code ‘1’.

This will occur if the minimum target platform version is set to 10.0.16225.0. To work around this, right click on your project file and choose properties or open your project file in your favorite editor, and change the version to a previous released SDK.

  Windows 10 SDK Preview Build 16267 and Mobile Emulator Build 15240 Released