To regenerate certificates for a full course roster, you must first go to the Instructor tab > Certificates.
Scroll down to the section called “Regenerate Certificates”.
Here you will see three options you can check. Check the option that says: “Regenerate for learners who have already received certificate”
This will start the regeneration process. Depending of the size of the roster, the process may take a few minutes to complete.
Users will simply have to re-download their certificates upon visiting the course and visiting their Progress tab.