The older Apple iPhone models like iPhone 3/3GS and iPhone 4/4s are not compatible with the 5GHz wifi frequency band. However, iPhone 5 and all-new models, including iPhone 6/6 Plus/ 6S/ 6S Plus/ SE/7/7 Plus/ 8/8 Plus/ and iPhone X/XI/XII, are designed to work with the 5GHz wi fi band.