In OLab3, there was a very crude authorization (or 'security') model with only 4 types of users: student, author, reviewer and superuser
Now in OLab4, we have proper role-based access, as is commonly seen with most Learning Management Systems.
There are a number of common roles available, typically in line with those seen in an LMS eg.
You can also define custom Roles that better fit your purposes. If you want to tailor access to certain cases or even parts of a case, you can now do so.
For example, we now have Role-Based Node Access - this means that you can lock a Node for certain roles. You might lock a Node (or even a whole pathway) so that only teachers can access some extra notes on how to coach learners through a difficult section.
In the map above, you can see this in action. You will not see the superuser options but, depending on your role in Moodle, you will be able to choose the Moderator role or the Learner Role.