I just called Sprint to ask when I can pre - order iPhone 7 Pro/Plus to find out if I change the phone there no way to re -active SERO Premium 500 like before. They took it off after July 7th, 2016. They said when I switch phone, any phone even back to temporary dinosaur flip phone if my iPhone 6 Plus now is not working, there's no way to activate any SERO plan to the different phone. So is only way to stay on SERO is using the same phone until it breaks. Well, might be it's time to switch to Ring Plus.