Samsung has added Google RCS (Rich Communication Services) in the last update which brings most of the instant messaging apps features such as chatting over Wi-Fi and mobile data, create group chats, sending photos and videos, ability to see if the other person has read your message and more.
In addition to Google RCS support and April 2021 security patch, the update brings improvements to Camera stability for a better camera experience. It is currently rolling out in India with firmware version A750FXXU5CUD3 and will head to other regions pretty soon. To manually check for the latest update on your Galaxy A7 (2018), simply navigate to Settings » Software updates. [source]