Each class now has a status property, which can be either “Under Construction” or “Established.” This indicates whether or not all of the lessons and assignments have been added to the entire class.
The class status can only be set by the creator, or another class administrator. It’s a way to indicate that the class has finally been fully built-out, and if a user is to complete all of the assignments, they should get credit for completing the entire class.
An established class can still be edited in any way, even to add more content. However, students need to have some kind of target to shoot for, and it wouldn’t make sense to take away credit for a completed class just because an instructor comes along later and adds something new.

