The Windows SDK is typically updated only when a Windows operating system or the .NET Framework reaches a major milestone or is released. Unfortunately, this leaves large gaps of time between SDK updates. Are there parts of the SDK would you like to see updated more frequently? i.e. Documentation, Samples, Tools, Headers, Libraries, etc.
The MSDN Windows SDK Developer Center is the place to find resources and links to Windows SDK products, release notes, technical articles, and more.