This release has some possibly breaking changes and a whole host of new features. There is also an installer available along with the zip archive. The HelloWorld example has been rolled into the zip file.
There is one minor feature addition: wsgi.file_wrapper is now supported for faster file transfers. It uses HttpResponse.TransmitFile to send the file directly.
The major new feature is IIS7 management integration, including a UI configuration editor. This is a huge addition and one I'm quite proud of. It makes configuring NWSGI a breeze from the command line (appcmd) or from the UI. The IIS7 integration is only available through the installer.
The changes are in the configuration system to support the IIS7 management system. Unfortunately, IIS7 doesn't use System.Configuration; instead, it has its own assembly, Microsoft.Web.Administration. This caused some complications for configuration. There are now three possible usage scenarios (IIS6, IIS7 xcopy, and IIS7 installed) that require slightly different web.config settings; these are described in the documentation.