Is it possible to upgrade installed Mini WAS 6/20 to 6/20?

I have MiniWAS 6.10 Test Drive installed. Can I upgrade it to 6.20, or will I have to do an uninstall and reinstall? I remember that the 6.10 Test Drive was adamant about not installing if a SAPDB had already been installed - I'm wondering if I'll have the same problem with 6.20?

Thanks...