Hi Wen,

It would be more effective to use Certifications just for the degree of control you have, but at the moment changes made are only applied to users added after the changes, there is an enhancement ticket in to include all users but I couldnt give a precise date as to when it will be completed.

I think also theres a bit of a debate to be had around changing course content and whether or not its actually a different course. It might make more sense to have a date-based naming convention for the new edited course, for example, 

hope this is useful,

Regards,

George.