5g SIM card into an older iPhone model
What would happen if I put a 5g SIM card into an older iPhone model?
iPhone 11 Pro Max, iOS 15
It will work, however, you will not receive 5G service on that older iPhone model if it is not capable of receiving 5G service. IPhone models 12 and 13 are the only models, currently, that are 5G capable.
Axel F.