Update processing of course deregistrations in Blackboard

Update 12-2: unenrollments from courses in OSIRIS are processed again in Blackboard since today.


Because of the Blackboard problems that occurred on January 20, there is a temporary change in the processing of the course deregistrations (precautionary measure): students are not deregistered from the Blackboard course after they are deregistered from the corresponding course in OSIRIS.