My son was given a brand new, unlocked iPhone 13. He never "activated" the new iPhone, he simply took the old SIM card out of his Samsung and everything worked fine, he says. I asked Verizon if there is anything else he needed to do and they said he might not be accessing 5G network without a new SIM. Is this true, or is he fine to just keep using the old SIM? Would there be any problems in swapping SIMs? Verizon sent us one that's just sitting on a desk.