Google bans self-updating Android apps, possibly including Facebook's
Android is far more permissive than iOS regarding the installation of third-party applications, even allowing installation from third-party sources if the user explicitly allows it. However, it's unusual for applications delivered through the official ...
Google outlaws Android app updates that don't come from its Play store
Google closes Facebook's loophole, bans non-Play Store app updates in Android
Want To Update Your Android App Outside Of Google Play? Well, You Can't