Currently there is no mechanism at all for setting up Certifications with set renewal periods and automatic notifications for Start, Due, and Expiry dates. A Certification would act as a "Wrapper" for single or multiple courses. Please work on this with the participation of the user community.
I am using a course shell for certifications that require classroom training provided by an outside vendor, such as a Forklift Trainer. The course does not contain any lessons; only a document upload. I complete the course as a System Admin. Completion results in a certificate with a three-year expiration (and automatic re-enrollment), a badge and a competency.
We have had to create a work around for certifications, which is not ideal. It would be great to be able to identify courses that are part of a certification (or various certifications) and allow students to purchase when they are ready (not requiring a curriculum set up which requires full payment at the start date).