Considerations for upgrading form templates that use managed code

If you created an InfoPath 2003 form template using one of the InfoPath 2003 Toolkits for Microsoft Visual Studio and you want to maintain compatibility with InfoPath 2003, you can continue to work on and further develop your form template project by opening it in Microsoft Office InfoPath 2007 and the Microsoft Visual Studio 2005 Tools for Applications (VSTA) environment, or in Microsoft Visual Studio 2005 with Microsoft Visual Studio 2005 Tools for the 2007 Microsoft Office System. When you do this, the business logic in your form template will continue to use the .NET object model provided by the Microsoft.Office.Interop.InfoPath.SemiTrust namespace.

Alternatively, you can migrate and upgrade the code in your InfoPath 2003 form template project to use the new .NET object model provided by the Microsoft.Office.InfoPath namespace. When doing so, all of your business logic code will need to be re-written to use members of the Microsoft.Office.InfoPath namespace, but all of the code from your previous project is retained and surrounded by #if InfoPathManagedObjectModel and