Weird thing I've noticed recently: I can normally exchange iMessages without any issues with my dad - but, right now if I start a new conversation with him, it does not go blue - its stays as green SMS. But when he tries the same from his phone, it will be the blue iMessage. When I receive this, it stays as the blue iMessage so I can reply as an iMessage. For some reason I can't start a blue iMessage conversation with him. Any thoughts? I've just tried restarting iMessage and my phone to no avail. Last night we were in the same room and it was still behaving like this.