Until then, here is how you can trigger the hidden Facebook Messenger Dark Mode. At the time of writing this feature isn’t enabled by default, nor available in the Settings area until you perform the trick described below. Once uncovered, Dark Mode in Facebook Messenger will also become available in the FB Messenger chat Settings.
5 Steps To Enable Dark Mode in Facebook Messenger
Fact: First of all make sure that your iPhone and iPad runs the latest Facebook Messenger version for iOS.
1. Open Facebook Messenger and select an existing chat or start a new conversation.
2. Tap on the Smiley face icon available in the text input area.
3. Select the Emoji tab.
4. Find and tap on the “moon” emoji. Next, end it to your chat partner.
Fact: This will trigger the “Dark Mode”! Facebook Messenger informs you that “You’ve found dark mode!”
5. A “Try it in Settings” tab becomes available at the top of the screen. Tap it and you will be redirected to the Settings area. Hit the on/off toggle next to Dark mode and you will enable the black theme.
Tip: On the Facebook Messenger homepage you can tap your profile photo, available in the top-left corner of the screen to unveil the Settings section. Here you can easily toggle the black theme on and off whenever you want!
Related: You might be also interested in the YouTube Dark Mode for iOS.