Enterprise Library 4.0

So it is here: Microsoft Enterprise Library 4.0.
Most important for this version is that it works only with .NET 3.5.
At my work we currently use Enterprise Library 2.0 but it lacks Validation and Policy Injection blocks. Those blocks are present in the 3.1 version that, for instance, works on both .NET 2.0 and 3.0.

For 4 or 5 days ago I downloaded this latest version to my workstation in order to test it and make a complete evaluation. Although we are not moving to .NET 3.5 it is important to follow Micorsoft's steps.

Compared to its predecessor, this version as some performance improvements, bug fixes, instrumentation support and VS 2008 support.