Microsoft has released Windows 10 SDK Preview Build 17125 to be used in conjunction with Windows 10 Insider Preview (Build 17125 or greater). The Preview SDK Build 17125 contains bug fixes and under development changes to the API surface area.
The build works in conjunction with previously released SDKs and Visual Studio 2017. You can install this SDK and still also continue to submit your apps that target Windows 10 Creators build or earlier to the store.
The updated SDK brings support for C++/WinRT, with the C++/WinRT headers and cppwinrt compiler (cppwinrt.exe) now included in the Windows SDK.
The 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. Authoring support is however currently experimental and subject to change. Microsoft intends to publish more detailed instructions on how to use the compiler in the coming week.
The update also introduces New MIDL keywords as a part of the “modernizing IDL” effort. These new keywords will cause build breaks if they are encountered in IDL files.
The new keywords are:
If any of these keywords are used as an identifier, it will generate a build failure indicating a syntax error.
The update also added a number of new APIs which can be seen in the blog post announcing the update here.
The Preview SDK can be downloaded from developer section on Windows Insider.