WhatsApp recently added a new feature that allowed users to delete a message within 7 minutes of sending it. This meant that if you were to delete a message before the recipient read it, it would show up as ‘This message was deleted’.
So, how would one find out what the message was? Well, apparently, the message would still be visible in the notification log of your device. You will just need a third party app to access the log.
If the message is a short one, then you can probably read what it is. However, long messages would be cut off, and you wouldn’t be able to read it fully. Even if the sender deletes the message, you will still be able to read it.
There are many apps available on the Play Store, that will record device notifications for you. When someone sends you a WhatsApp message, it will first appear as a notification, and that would be stored on your device. One such application, that does this, is called Recent Notification.
After downloading this app on your device, and enabling notification access, you can start logging your notifications. There are no in-app purchases, and nor does the app require any permissions or data connectivity. The notifications you receive are grouped according to the apps and by day. So, whenever you receive a notification from WhatsApp, it will be stored on your device thanks to this app.
via Android Jefe