The way they see it, Facebook Groups, which let like-minded users communicate outside of the main News Feed, is an integral part of social network’s future as it passes the 2 billion user mark.
So it may have come as a surprise to see the company quietly removed its standalone Groups app from the App Store and Google Play last week. If the social network is suddenly so into groups, why would it pull the app dedicated to the feature?
from Mashable http://mashable.com/2017/08/09/why-facebook-killed-groups-app/
via Facebook Page