Early betas were even labeled as macOS 10.16, and Big Sur can still identify itself as version 10.16 to some older software in order to preserve compatibility. Further Reading macOS 10.15 Catalina: The Ars Technica reviewīut unlike the jump from Mac OS 9 to Mac OS X, where Apple swept away almost every aspect of its previous operating system and built a new one from the foundation up, macOS 11 is still fundamentally macOS 10.
