I was messing around with the FaceTime app to see how it sets up and disconnects calls. To view the traffic I set the phones proxy to a Paros session, which replaces any SSL certs with its own. On previous versions of the IPhone firmware when it received a self signed/out of date certificate it would present the user with a generic accept decline option and not give a lot of detail.

It seems apple are pulling their finger out and the error is much more verbose allowing the user to see exactly what’s wrong.