For Carbon Black App Control agent 8.7, kernel extension is supported on macOS 10.14.x Mojave and macOS 10.15.x Catalina. For Carbon Black App Control agent 8.5 and 8.6, kernel extension was supported on MacOS 10.14.x Mojave, macOS 10.15.x Catalina and macOS 11.x BigSur.
The macOS version 10.13 (High Sierra) introduced changes in the way kernel extensions are handled.
If you are installing or upgrading the Carbon Black App Control agent on any version of macOS 10.14 (or later), additional steps are needed to approve the Carbon Black, Inc. system extension, which is required for proper operation of the agent.
This is true for manual agent installations and upgrades as well as those initiated from the Carbon Black App Control console
This requirement does not apply if you are using a version of macOS prior to 10.13, and if you are using Carbon Black App Control agent 8.7+ on macOS 11.x or later.
For a KEXT support matrix, see: Kext and System Extension Support