Windows 10 SDK Preview Build 17115 released.

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

Things to note:

  • This 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 Windows SDK will now formally only be supported by Visual Studio 2017 and greater.

Known Issues

  • Installation on an operating system that is not a Windows 10 Insider Preview build is not supported and may fail.

What’s New:

  • C++/WinRT Now Available: The C++/WinRT headers and cppwinrt compiler (cppwinrt.exe) are 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. The easiest way to get working with it after installing the Windows Insider Preview SDK is to start the Visual Studio Developer Command Prompt and run the compiler in that environment. Authoring support is currently experimental and subject to change. Stay tuned as we will publish more detailed instructions on how to use the compiler in the coming week

Breaking Changes

  • New MIDL key words.

As a part of the “modernizing IDL” effort, several new keywords are added to the midlrt tool. These new keywords will cause build breaks if they are encountered in IDL files.

The new keywords are:

  • event
  • set
  • get
  • partial
  • unsealed
  • overridable
  • protected
  • importwinmd

If any of these keywords is used as an identifier, it will generate a build failure indicating a syntax error.

The error will be similar to:

1 >d:\os\src\onecore\com\combase\unittest\astatestservers\testserver6\idl\remreleasetest.idl(12) : error MIDL2025 : [msg]syntax error [context]: expecting a declarator or * near “)”

To fix this, modify the identifier in error to an “@” prefix in front of the identifier. That will cause MIDL to treat the offending element as an identifier instead of a keyword.

Read more about API Updates and Additions here.