In the Essentials course, it is possible to use Automatic Level Adjustment. If Automatic Level Adjustment is enabled, students will automatically move between levels depending on their grades. If a student gets four consecutive marks of 8 and above, they will go up a level. If they get four consecutive marks of 4 and below, they will go down a level.
You can enable or disable Automatic Level Adjustment via Teach > Course settings. Tick 'Use Automatic Level Adjustment', check if all other settings are right, select the classes you want to apply the settings to and click 'Submit'.