Change 1: Manual Registration Now
Aspose.Words.dll is a .NET class library, but you can use it via .NET COM Interop from many other languages such as ASP, Delphi, JScript, Perl, PHP, Python, C++ etc. In order to use Aspose.Words.dll from a COM client you need to have it registered for COM Interop.
The change is that Aspose.Words for .NET 9.1 does not register Aspose.Words.dll for COM Interop automatically during install. In earlier versions Aspose.Words.dll was registered automatically.
While we are still considering pros and cons and deciding whether to return the automatic registration or not, you can easily register Aspose.Words.dll for COM Interop manually, please see http://www.aspose.com/documentation/.net-components/aspose.words-for-.net-and-java/use-aspose-words-for-net-via-com-interop.html
Change 2: No IDL Anymore
We used to supply Aspose.Words.TLB and Aspose.Words.IDL together with Aspose.Words.DLL in versions earlier than 9.1. Now we decided to try and not supply the .IDL file anymore. Please let us know if you need and cannot generate yourself. If there is a lot of feedback, we might have to put it back in.