This is something that irritates me. Clients don't mind running old version of X (browser, operating system, hardware, w/e), but they require the latest version

This is something that irritates me. Clients don't mind running old version of X (browser, operating system, hardware, w/e), but they require the latest version of your product. If they're going to stick with windows XP, they should be happy with the software which was written for and when windows XP was supported.