Facebook Messenger's Dark Mode is now available for activation
According to a recent Reddit page, Facebook's long-awaited dark mode for its Messenger feature can now be activated. This can be done by sending a crescent-moon emoji in the app's chat field to anyone (oneself included), then tapping on this character in the resulting post. Thereafter, a pop-up will appear informing the user that Dark Mode is available, at which point said user can navigate through the settings to toggle it on.
A Redditor had found and posted on this new addition to Messenger before Facebook officially announced it. It may be that the company wanted users to discover it for themselves, which could have led to a good deal of word-of-mouth popularity for the new mode. This apparent strategy appears to have succeeded, as it has been discussed extensively on the resulting Reddit page since.
Messenger's Dark Mode should work on both iOS and Android. However, some users have complained that they have not received access to it after sending the emoji. Exiting the app and then returning to it via Recents may address this in some cases. In others, users have had to restart the app before searching for the mode in Settings.