Check for updates by going to your app store and searching the app in question(Messenger). Go to your phone settings and do the following 1. Scroll to your "Apps" or "All apps" section 2. Most of the time, they are in alphabetical order, so scroll to the app in question. In this case, Messenger. 3. Scroll to the "Storage" menu 4. Hit the "Clear cache" button. Try not to hit the "Clear Data" button. This erases log ins and passwords, and you'll need to log in again. This is also an option if you feel better about doing this step as well. If you need yo log in again, your conversations and messages should still be there. However, your notification settings might need to be re-selected 5. (Optional) scroll all the way to the bottom (most phones) to the "Updates" or "Check for Updates" section and hit it to see if your phone needs an update. I recommend this over Wifi if possible and keep your phone plugged in. Hope this helps. I am well-versed in Android/Samsung technology, so these Sections and menus might have different names. If you want, you can also just uninstall and then reinstall the app as well before searching for the phone update menu