What someone says about you after the contract doesn't work out matters.

Nope. Nothing was assumed. For the first few years of the contract we hosted it. They wanted to move to a Windows platform well after the application was built and in use for several years. The conversion to Windows was itself a separate contract.

With PHP itself? None. With that particular application we had relied on Apache's mod_rewrite and had some code that made some assumptions about how file system permissions worked. Not intentional assumptions, mind you, but assumptions just the same. So, naturally it blew up in our face. heh.