>Legally, if you do an upgrade, you must stop using your previous version. I'm pretty sure that's what they're trying to tell you with the second sentence.

You can upgrade from VFP 6.0 or VFP 7.0 to VFP 8.0 and keep the older version(s) of VFP installed and using those version at the same time, no problem. Developers need to maintain applications that use older versions of tools, which is why for example MSDN Subscriptions still includees Visual Studio 6.0 (with VFP6 and VB6), VS .NET, VFP 7.0, and now VFP 8.0 all together. The only issue here is "installing" VFP 8.0 into the same directory as a previous version of VFP installed.