I have a basic compatibility problem with emoji: the emoji available on one Android device (Android 8.1) do not match those available on a second (Android 6.0?) in applications including the SMS messaging application or Google Hangouts. Some emoji show up as blank boxes on the receiving end.
Is there a way to update the older Android device to include newer emoji? Assume that the messaging applications such as Google Hangouts have the latest updates for their respective platforms and that the receiving device is a normal end user device that is not rooted.