Facebook has a new dark mode for Messenger, and it’s a true OLED black theme. It’s was hidden away in earlier versions and you needed to either run a root hack or send a moon emoji to activate it — but now, you can enable dark mode by toggling a simple switch in Facebook Messenger’s settings.
https://smartphones.gadgethacks.com/how-to/activate-dark-mode-facebook-messenger-0192439/

