M365 Groups (Information) Groups Mobile App Retired
The app was removed from the Apple App Store, Google Play Store, and Microsoft Store and no longer worked as of May 1, 2018. Anyone who attempts to open it will be greeted with a message directing them to download the Outlook mobile app.
For information on how to use Groups functionality within the Microsoft Outlook app, please go to Microsoft's documentation by navigating to Use Groups in the Outlook mobile app