<class1> property <class1>.<prop1> was upgraded to <class1>.<prop2> which has a new behavior
During the upgrade process, some class members and events can be mapped to a .NET equivalent with minor behavior differences. If this EWI is displayed in a given project, the selected source structure will not threaten the functional equivalence of the resulting code but can require some manual fine tuning.
Compare the new .Net members and events to the old ones and verify their behavioral equivalence.
MSDN contains some lists as well as documentation on these equivalences: Windows Forms Controls for Visual Basic 6.0 Users