http://developers.de/blogs/damir_dobric/archive/2009/05/31/code-contracts-in-net-4-0.aspxSince Visual Studio 10 BETA 1, the code contract library is fully integrated in .NET Framework 4.0. The VS 10 BETA1 installs by default the framework version 4.0.205506. In installation folder of .NET 4.0 there is as usual assembly mscorlib.dll whichenCommunityServer 2008 SP1 (Build: 30619.63)