I heard somewhere all iPhones are unlocked till you enter the phone providers SIM card in and then it automatically locks to that phone provider. I've tried to search this but can't find it anywhere.
I'm asking as my contract is due for renewal (ee) and my son wants the upgrade but he is another phone provider (o2) so was wondering if his sim will work in this?
Many thanks in advance
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Is a iPhone unlocked till you put a sim in?