Versions of Mac OS X 10.11 and newer have a rewritten USB stack that is substantially less compatible than that in 10.10 and below. HoRNDIS 9.0 has been rewritten to support MacOS 10.11 and above (El Capitan, Sierra, High Sierra, and Mojave); for those versions of MacOS, please try the latest version of HoRNDIS! The latest version of HoRNDIS that supports older versions of MacOS (Yosemite and below) is HoRNDIS rel8.
of course, it's not like the native ECM driver could be stable for longer than from 10.10 to 10.14 ... now it seems that there is need for horndis 9.2 on Catalina (10.15): https://forum.bela.io/d/1025-macos-catalina-usb-connection-does-not-work/2
From the dev site (wrt versioning):
see https://forum.bela.io/d/1025-macos-catalina-usb-connection-does-not-work/2