Use priority MIN for expired digest notification.

        // Remove the title in the expanded form (redundant with the listed items).

        expandedBuilder.setBigContentTitle("");

        // Set to a low priority to encourage the notification manager to collapse it.

        notificationBuilder.setPriority(Notification.PRIORITY_LOW);

        // Set to min priority to encourage the notification manager to collapse it.

        notificationBuilder.setPriority(Notification.PRIORITY_MIN);

        return expandedBuilder.build();

    }