Facebook is working on a dark mode for Messenger. This is a real AMOLED Black theme. It's currently hidden, but most of the code is there, waiting to be activated. If you send a command with root access, you can now enable this feature.
Access Redditor VincentJoshuaET, who discovered the method we outlined below. Unfortunately, this does not work for iPhones and it does not even work with ADB commands on Android. So you must use the root mode to try the hidden dark mode in Messenger. However, all you have to do is run a command in a terminal emulator app, tap some options in a hidden menu, and then turn on dark mode in Messenger.
Because the hidden / unactivated Dark Mode code is only included in the latest Facebook version of Facebook Messenger, you must update the app. The easiest way is to load the new version of APKMirror from the sideload. Just tap the link below, scroll down and press "Download APK." From there, launch the file from the notification area and tap Install to update Messenger.
Once If you have the latest Facebook Messenger beta version installed, open the app and sign in on. If you do not do this now, you will not be able to activate the hidden mark menu later.
You must execute a root command to enable the dark mode. This means that you need a terminal emulator app. You can use any of these apps of your choice, but if you need a recommendation here, choose the proven terminal emulator from Jack Palevich.
Now open your terminal emulator app, type "su" (without quotation marks) and press Enter on your keyboard. You will be asked to give the app superuser access (terminal emulator, not Facebook Messenger). Therefore, tap "Grant" in the popup. You will now notice that the second command line starts with a hashtag instead of a dollar sign – meaning that the terminal is running with elevated privileges.
Then copy the following command, paste it into enter the terminal prompt and press Enter on your keyboard:
at start -n "com facebook.orca / com.facebook.abtest.gkprefs.GkSettingsListActivity"
You will be immediately taken to the "hidden flags" menu. led by Facebook Messenger, where low-level optimizations can be applied to the SMS app. Tap on "Find Gatekeepers", enter "dark" at the prompt and click "OK".
Then tap each of the results under the header dark to get the values of "NO to change to "YES". If all three say "YES," leave this menu and close the Facebook Messenger app completely by swiping it from your last apps menu.
Now open Messenger and tap on your profile picture (or silhouette icon) in the upper left corner to access the main settings menu of the app. From here, scroll to Preferences and you'll see a new option that was not there before. Activate "Dark Mode" and tap on "OK" in the popup to confirm your selection.
Messenger is now completely black with white text and dark gray accents. Although the popup you have just seen said, the dark mode "is not displayed everywhere in Messenger", all major menus have received the dark mode treatment.