Discover if using the 'mark as unread' feature on facebook reverts messages back from 'seen' status This limitation may be a drawback for users who primarily use messenger on their phones. Get clarity on managing your message notifications.
Signal Mark Unread at Zane Stirling blog
The feature is designed to provide users with the flexibility to manage their conversations without drawing attention to specific interactions
So, if you mark a message as unread on messenger, it’s a subtle way to keep track of messages you haven’t addressed without triggering a visible alert for the sender.
Select the option mark as unread This has led many people to think that they can read a message without letting the sender know it has been read and it does work that way. Overall, the ability to mark messages as unread enhances the user experience on messenger and strengthens communication efficiency However, it is worth noting that this feature is only available on the desktop version of messenger and not on mobile devices