His question asked if the forwarding still applies if the phone becomes unregistered. The answer is no. But there is a newer feature call Call Forward Not Registered (or something like that) that does what you're asking about. I can't remember what version of CM has this. I think it started in 4.2. IIRC, 4.1 does not have it at all. I'm not even sure 5.0 has it, but 5.1 and later probably does.