Why is UPI not working on iPhone 6?

UPI is not working on the iPhone 6 because its operating system is limited to iOS 12. According to NPCI security standards, UPI services require a minimum of iOS 13.4 or higher to ensure secure transaction protocols and fraud prevention. Since the iPhone 6 and earlier models cannot be updated to these newer iOS versions, they no longer meet the essential security criteria for processing UPI payments. To continue using UPI, you will need to upgrade to a device that supports iOS 13.4 or later.