What are the requirements for Touch/Face ID login?

Touch ID login for the American Express^® App is only available for iPhone 5s and above, running iOS8 or higher. Touch ID must also be enabled for your device. To enable Touch ID for your device, go to Settings>Touch ID & Passcode. Face ID login for the Amex App is only available for iPhone X and above, running iOS10 or higher. Face ID must also be enabled for your device. To enable Face ID for your device, go to Settings>FaceID & Passcode.