Please note: This is an N edition of Windows.

Release Notes: Important Issues in Windows 8.1
Appendix A: KMS Client Setup Keys
This table provides the volume licensing keys for relevant Windows 8.1 and Windows Server 2012 R2 editions.
Download Windows 8.1 RTM app samples
This sample pack includes all the app code examples developed and updated for Windows 8.1 RTM. These samples should only be used with the released version of Windows 8.1 and Visual Studio 2013 RC. The sample pack provides a convenient way to download all the samples at once. The samples in this sample pack are available in C#, C++, and JavaScript.
Download the Windows 8.1 WDK
Download the Windows Assessment and Deployment Kit (ADK)
Windows 8.1 SDK
The SDK is included with your installation of Visual Studio 2013 RC