The Unification Theological Seminary periodically offers an advanced online course on the Divine Principle, which considers the main topics of the Exposition of the Divine Principle in light of True Parents’ extended teachings, the text’s Judaic and Christian roots, as well as the earliest expression of True Parents’ thought still available to us, the Wonli Wonbon.
The most expedient way to know when the course will next be offered is to sign up for the uts.edu newsletter or else to check the listing of online classes posted at the link below. The new semesters start in late August and early February of each year, and class listings are most often posted about a month in advance (in July and January, respectively).