WhatsRemoved+ is an app that lets you detect any change in a message. Thus, if someone sends you a message and deletes (or edits) it for any reason before you can read it, you have the possibility of recovering it and looking over it in its original format.
Upon installing WhatsRemoved+ you can pick which apps you want to monitor. You can select as many apps as you wish, keeping in mind that when a message from one of these apps gets modified for any reason, you'll get a notification. Of course, this could be especially interesting for IM services like WhatsApp or Telegram, where you can edit or delete text messages. And also for social networks like Twitter, where someone can delete a tweet.
WhatsRemoved+ is an interesting app that should be used with a dose of prudence. In the end, if someone has deleted a text message or photo before you could view the content, it's because they didn't want you to see it. And if you do, you're betraying their trust.