With Visual Basic 5, Visual Basic becomes a 32-bit–only development tool. The 16-bit build of Visual Basic 4 was the last tool created that you can use to develop Visual Basic programs for the Windows 3.x platform. I understand that the 16-bit build of Visual Basic 4 will be maintained in much the same way Microsoft Visual C++ version 1.5 has been maintained to provide a 16-bit C++ compiler.
About the only valid reason I can think of not to convert to Visual Basic 5 is if you want to develop programs that will run on all three popular Windows platforms, Windows 3.x, Windows 95, and Windows NT. However, even if this is the case, you cannot ignore these issues completely because you still have to face the shell and Microsoft Office issues discussed later in this chapter if your program is ever run under Windows 95 or Windows NT Version 4.