Google has put its foot down when it comes to how Google Play applications are updated. From now on, now app that’s installed from Google Play can apply updates without going through Google. The Google Play Developer Program Policies explicitly states, “An app downloaded from Google Play may not modify, replace or update its own APK binary code using any method other than Google Play’s update mechanism.”
This update to the policy comes weeks after Facebook infamously updated its app without using Google Play. Facebook users were given a prompt to apply an update that was distributed by Facebook instead of Google.
Developers won’t be allowed to push non-Play updates to their applications even if users allow installations from third party sources. This rule doesn’t apply to applications that are installed outside Google Play. You assume risk by downloading applications that haven’t been vetted by Google. Google is making sure it eliminates the chance of getting blamed if a developer pushes a malicious update to its app that Google allowed in the Play store.