New Two-Step verification on older iOS devices

See the following from Two-factor authentication for Apple ID - Apple Support

If you use two-factor authentication with devices running older OS versions—like an Apple TV (2nd or 3rd generation)—you might be asked to add your six-digit verification code to the end of your password when signing in. Get your verification code from a trusted device running iOS 9 and later or OS X El Capitan and later, or have it sent to your trusted phone number. Then type your password followed by the six-digit verification code directly into the password field.

See my previous reply above. It has instructions on how to sign into devices running older iOS versions.

You can sign in on older versions but the code can be sent only to a) a device running iOS9 or later or El Capitan or later or b) a trusted phone number. The trusted phone number can be any number including an Android or landline.