There are covid-19 apps restricted to BLE and iOS 13.5 and above only. There are so many iPhone 5s, iPhone 6 etc. still in circulation (they won't allow installing iOS 13.5), therefore I wish to know where exactly this restriction takes place.
1) Does iPhone 5s and iPhone 6 have technology that would allow a covid-19 app based on nearby Bluetooth devices work?
2) Exposure Notifications is supported on iOS 13.5 and above only. What is this restriction based on (hardware features or something else)?
3) Would it be theoretically possible to add Exposure Notifications to iOS version supported by iPhone 5s and iPhone 6?