Voila ce que l'on trouve sur leur site :
"Unlocking your iPhone in order to transfer service to another carrier
Consistent with the Terms & Conditions you agreed to when you signed up for service, AT&T customers cannot unlock their iPhone to work on another network. Unlike some of our major competitors, AT&T uses GSM technology. iPhones designed to work on AT&T's network will not work on another carrier's network.
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What should I be aware of if am considering transferring my iPhone to another carrier?
An overview of Early Termination Fees
View contract end date
The advantage of AT&T's data plans vs. plans offered by other carriers"
Je l'ai définitivement dans l'os ... Et impossible de les contacter à moins d'avoir un numéro américain ou de les appeler directement mais ça doit taxer