After Facebook was found to be updating its Android app without using the Google Play store's update mechanisms, Google has clarified its terms and conditions to ensure no other developers attempt to circumvent its store. While Google has always outlawed "applications that cause users to unknowingly download or install applications from sources outside of Google Play," it's added a new sentence to its "Dangerous Products" section:
"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."
Google's new phrasing leaves little room for interpretation. Facebook's justification for its update policy was that it was only pushing the updates to users that allowed non-Play store downloads to their phones, and it was informing them that the update was available. That worked under the old terms and conditions, but it's clear that Facebook will now have to stop its experiment of pushing new features to users that allow installations from unknown sources.