Was using a TracFone iPhone 6S. Bought an iPhone SE3 from Apple Store. After several hours with TracFone Tech Support and failure of two different "Keep Your Own Smartphone" SIM cards, we finally moved the 6S' SIM card to new SE temporarily. TracFone sent me a new SIM card for permanent replacement. New phone works fine; why do I need the new SIM cards?
Hi Steve. It's so you can experience a faster mobile data speed. I believe you can opt not to use it.