"The Microsoft® Windows® Software Development Kit (SDK) provides the documentation, samples, header files, libraries, and tools you need to develop applications that run on Windows. The applications you develop with this edition of the SDK can run on the x86, x64 and Itanium-based versions of Windows Server 2003, Windows Server 2003 R2, Windows XP SP2, Windows XP x64 Pro Edition, and Windows 2000. The Web install allows you to select components you wish to install on a more granular level.

The Windows Server 2003 R2 PSDK is a minor upgrade that adds a few features targeted for the Windows Server 2003 R2 release. Therefore issues you might have encountered with the Windows Server 2003 SP1 SDK and Visual Studio 2005 are for the most part unchanged with this release. The release still includes the 64 bit compilers that released with the SP1 SDK, ( it does not include x86 compilers). Although these compilers are on the same code base as the ones later released in Visual Studio 2005 – the Visual Studio compilerss continued to have enhancements introduced to them, long after these were released, you will find differences between them. (For example if you use the VS 2005 compilers, and the VC libraries from VS 2005 – you will not need to link to bufferoverflowu.lib. While it is perfectly acceptable to continue to use these compilers for production code – you should consider moving to the enhanced versions in Visual Studio 2005.

This edition of the SDK replaces the previous SDKs for Windows XP SP2 and Windows Server 2003 SP1 and can be used to develop applications for those platforms.

Some additional changes include, a new setup that will not automatically un-install the previous release, samples have been tested with both Visual Studio 2003 and 2005 and those that do not work with both are documented in the release notes. Additionally there were some mismatched MFC libraries (both debug and retail) and these have been corrected. "