Do find new layout screenshots and new features details below.
Facebook is testing new UI for users, which also include top level tabs and instant game section in the bottom Nav bar.
Below is the screenshot of the new app UI.
First change which we observed is, developers added tabs below the search bar. Instead of active users line all the sections have been splits into distinct tabs.
The developers also moved Groups tab to the bottom nav bar. Practically, These changes seem to make sense, with all of your conversations and online contacts in the tab navigation. As the most used options these are now rightly front and center.
There is a new Game console icon added in the bottom nav bar where you can find the games.
Download Below APK file to get all these features
Facebook Messenger APK