In such case you're in DLLHell and there's no way out.

>I understand what you are saying... but that solution assumes you have the source code for all apps in use. Just for fun, consider this scenario: Lets assume that you install a commercial app (with no source code) on your server, and assume that the app uses VFP OLEDB and was developed with the OLEDB driver associated with V8 of VFP. Later, on the same server you install another vendor's app (a completely different app, not a replacement) or maybe install your company's own app, and it either requires or happens to also install OLEDB for VFP9, thus upgrading the V8 driver. I can see this happening pretty easily with web apps that use ASP and OLEDB or something similar. Suddenly the legacy app breaks and you are stuck with a mutually incompatible version conflict because there's nothing you can do about the app(s) for which you don't have source code. It's not the first vendor's fault that you installed a new DLL that broke his perfectly working code.
>