The change or pre-req from CS 641 Foundations in Data Science to CS 601 Programming Methods for Data Science or BS in CS or Equivalent recognizes that the real content needed for 661 is strong programming skills, rather than the knowledge in 641. The new pre-req parallels the pre-req for the coupled undergraduate version CS 461 which has CS 102 Computing and Algorithms II as its pre-req.
Farmer, Michael, "2/17/2021: Course Change Form CS 661" (2021). UCC Documents. 17.