The particular version of the .NET Framework we target in this book is .NET 4, using Visual Studio 2010 and C# 4.0. Other than the .NET 3.x releases, .NET 4.0 has a new version of the CLR underneath it, and obviously—in the grand tradition—it comes with a bunch of new class libraries that will make life easier for developers.
Two keywords about .NET 4.0 are important to point out here:
• Side by side means .NET 4.0 can be installed next to existing versions of the .NET Framework. What’s so special about this compared to .NET 3.x? The key difference is updates to existing class library assemblies are no longer carried out in-place, but new versions are put next to the existing ones.
• Backward compatible is a core success factor ...