Moving Sim to a new device
My partner has upgraded from iPhone Xr to an iPhone 16, same network but a different contract. My son has got the new phone working but told us we do NOT need to move the SIM and said it is a “SIM-less” phone. But nothing is working properly and calls and messages are still coming through to the old phone! Surely we need a SIM in the new phone and need to transfer it to the new device?! Help please!
iPhone XR, iOS 17