We are working hard on getting the .NET 4.0 version of the Design Pattern Framework ready.
Currently it looks like the release date will be late June / early July.
BTW: your purchase comes with a 1-year subscription which means you can freely download upgrades and enhancements during that period. The .NET 4.0 release is within this timeframe, therefore your purchase includes both the .NET 3.5 and the NET 4.0 versions.
Hope this helps.
Dan McMillan, May 19, 2010