With the forced unbundling of Facebook’s messaging feature to become Facebook Messenger, it is natural that the app will become the number 1 app on the Apple App Store. However, this change is also showing how people do not like being forced to download new apps that another app already does. The current version of the Facebook Messenger app has been getting one-star ratings from users. It is mostly attributed to the switch as the previous versions of the app usually earned a four-star average on the App Store.
Source: Mashable