Background: Apple is abolishing (third-party) kernel extension to increase security:
[1] https://www.opengroup.org/openbrand/register/
EDIT: I can't find anything that references kernel extensions in the conformance [2] section of the spec, so maybe 10.16 will adhere to the UNIX03 standard after all.
https://blackberry.qnx.com/en/resource-center/qnx-certificat...
UNIX certification doesn't say anything about how a kernel should be implemented, or what kind of driver architecture is used.