According to an announcement from MyHeritage:
“The Theory of Family Relativity™ harnesses billions of family tree profiles and historical records on MyHeritage to suggest possible relationship paths between you and your DNA Matches, helping you to break down brick walls and potentially saving you dozens of hours of research.
“With this update, the total number of theories has increased from 33,373,070 to 39,845,078 — a 19% increase. The number of DNA Matches that include a theory has increased by 20%, from 22,618,962 to 27,130,989.
“As MyHeritage users add more names to their family trees and as we add new historical record collections, the opportunities to receive theories will continue to grow, offering new insights to help you further your genealogical research.”
You can read a lot more details in the MyHeritage Blog at: https://blog.myheritage.com/2021/02/update-to-theory-of-family-relativity-4/.