Does unopened fully paid iPhone need to be activated with AT&T sim card before using with another?
I have bought a new unopened iPhone XS Max (GSM and CDMA) and the seller told me that it is fully paid off and can be activated on any GSM.
So when I open the box, do I need to insert AT&T sim card to finish the activation or can I put any sim card and start using the phone?
The problem is, that the place that I live doesn't have AT&T and I am afraid, that because of that I won't be able to activate the phone.
Please answer ASAP so I can know how to deal with the seller.
Thanks in advance