In "App store" you can set the configuration and customization of the desired app. The "Maintenance" tab is the place where you configure possible downtime or scheduled maintenance of the app. Additional settings like "Settings" and "Who has access" is described here.
If you enabled the maintenance you can schedule one maintenance window for the app. You need to configure the "Starts on" and "Ends on". You can add extra text to the standard "Notification message". The default included text cant be changed.
If the maintenance window is scheduled, you will see the following indication in "App Store". The user won't see the indication on the connected tiles.
If the app is under maintenance, you will see the following indication in "App Store". The user won't see the indication on the connected tiles.
During the scheduled maintenance window, the tiles connected to this app will be greyed out. And the user will receive a notification message if they trying to open the app.