Android 8.0 limits the activity of Workspace ONE Boxer app when users do not interact directly with it. This results in OS stopping the background sync operations prematurely.
To continue to receive the real time notifications you must deploy Email Notification Service 2 and disable the battery optimization for Workspace ONE Boxer. For more information on deploying Email Notification Service 2, see Introduction to Email Notification Service 2.
Workspace ONE Boxer posts a notification on the system bar to perform operations when the app is backgrounded. This notification is required to prevent the OS from killing the app in the background. In addition, disabling battery optimization is necessary to allow Workspace ONE Boxer to perform network operations once in the background.