Visual Studio Tools for Office: 2003? 2007? Version Compatibility

With Visual Studio Tools for Office (VSTO), Microsoft has add some impressive development capability to build solutions on top of Excel, Word and even Outlook now. You may have even heard that notion that Office can be considered part of the Application Platform, which includes things like Smart Client, ASP.NET Web, Compact Framework, BizTalk, etc. etc. However, one of the questions I've had about this was related to versioning. If I build a VSTO solution on Office 2003, will it work with Office 2007 now that it has been released and your customers may start using it. What about new development on Office 2007 - will those work on 2003?

Well today I got a pretty definitive answer from Tim Heuer at Mircrosoft that I'll share.With Visual Studio Tools for Office (second edition) you can create office 2007 add-ins as well as Office 2003 add-ins. What about documents? VSTO second edition doesn't allow you to target directly Office 2007 for document level programming. However an document targeted for 2003 would work in 2007. Not bad.