Hi All, I'm from Australia (AU) I'll be headed to the US in December, I plan to take my iPhone 6S Plus (iOS10) with me and pickup an AT&T sim whilst I'm over there. I have a few questions for those a bit more knowledgeable: -How will iMessage react when I remove my AU SIM Card and insert the US SIM? Do I need to change/update any settings etc? -Will I still be able to send/receive iMessages from people who have me registered with my AU number with the US SIM in my iPhone? If it makes any difference I have my AU phone number and my Apple ID E-Mail address registered on the iPhone as 'Send & Receive' adresses. Any advice would be greatly appreciated.