On January 1, 2020, Verizon is transitioning out of CDMA. The impact on iPhone users is minimal EXCEPT for users of iPhone 5 or older. Those phones will no longer work. Period. Users will need to purchase and begin using new(er) phones before the transition to avoid loss of service. Gazelle.com and other sites selling certified refurbished devices are good sources for used phones. eBay sellers with many sales and 99+% rating might be OIK. Craigs List and such, I’d be very careful, as stolen phones could be sold there. Good phones too, but be cautious.