It is possible to activate push notifications for the mobile app either in the web browser or directly on the mobile app
It is very important that notifications are activated on your mobile device. You may activate your mobile notifications for apps in your mobile settings.
In your mobile app click on the bottom right click on the hamburger icon 
after that click on 'notifications'. Here it is possible for you to activate notifications.
In the web browser, each user can activate their notifications themselves. To do this, click on the profile in the top right and then select the sub-item 'Notifications Settings':