Want to check your Facebook messages without setting off the 'Seen' notification?
For those times you're not ready to reply back to messages, there's two ways you can do it without letting the other person know you've already read it via mobile.
1. Turn on your push notifications.
By doing so, you may be able to catch what the message is from your notification screen, without needing to open the Messenger App.
2. Switching on Airplane Mode.
This safe mode is a sure fire way to read unread messages without being "seen" because your internet connection will temporary be switched off, and Facebook won't be able to send back a 'read' receipt.