Microsoft today released Windows 10 SDK Preview Build 17110 to developers. This SDK can be used with Windows 10 Insider Build 17110 or later. And this release includes bug fixes and under development changes to the API surface area. This Windows SDK will now formally only be supported by Visual Studio 2017 and greater.
As you might have noticed in the recent SDK preview releases, this release also includes the C++/WinRT headers and cppwinrt compiler (cppwinrt.exe). This compiler comes in handy if you need to consume a third-party WinRT component or if you need to author your own WinRT components with C++/WinRT.