Some Windows programs use Shell.Application object (sample: http://bugs.winehq.org/show_bug.cgi?id=8987). This object has IShellDispatch, IShellDispatch2, IShellDispatch3, ... interfaces (http://www.com.it-berater.org/COM/windows_shell/interfaces/IShellDispatch.ht...). If IShellDispatch is sufficient for some application and I am going to add its declaration should I add IShellDispatch2, 3, ..., 5 in addition?