Hi Mike, my error about the Mobility, it was an earlier version in which it wasn't included. I hadn't read my up-port list correctly. Through testing, we found that persistence was still required, the mobile client simply didn't log in on certain platforms. I am pretty certain that this was a Multiple SIP Domain environment, but we just enable it by default for compatibility reasons. If you have a way for me to contact you privately I'd be able to share with F5 the iApp changes I've made for you to refer to, if that's useful.