How to Present Unread Count Badge on the App Icon?
The ability to present a badge on the app icon is a property of the home screen manager or “launcher” of your device.
We support app badge for the native launchers of many devices, as well as some common 3rd-party launchers.
To select which account’s unread count to present on your main app icon: set it up with More… | Global Settings | Unread Count | App Badge Number and select your desired account.
For other cases please check Alternatives to Unread Count Badge on the App Icon.