Google released Smart Reply for Android Messages in September of last year. Smart Reply is a predictive text feature, which currently works in apps like Allo, Gmail, Inbox and from now on, Android Messages too. Functionality gives you the ability to answer messages by selecting pre-written responses based on machine learning an AI. Unfortunately, until recently it was only available for Project Fi users. As it turns out, Google decided to expand this feature to other carriers as well.
This is the first time we’re seeing Smart Replies in Android Messages for other carriers than Project Fi. Google tried to extend the functionality to other apps before. They released a beta version of Reply earlier this year. But, as you may already know, it only works in the notification shade, not in actual apps.
Adding Smart Reply functionality is caused by a server-side change on the latest version of Android Messages. We recommend all of you to update the app to the latest version and wait for Smart Reply to appear.