As part of macOS Catalina 10.15.4, Apple has begun displaying a new dialog window message concerning third-party kernel extensions. macOS Catalina is the last macOS to fully support the use of kernel extensions and these messages are meant to notify users of the following:
- macOS had detected that a third-party kernel extension had been loaded.
- The loaded kernel extension would be incompatible with an unspecified future version of macOS
To further reinforce the message that kernel extensions are going away, Apple refers to them in the message window as “legacy system extensions”. System extensions were introduced as part of macOS Catalina and are Apple’s replacement for kernel extensions.
As of macOS 10.15.4, these messages are informational only and do not indicate that anything is wrong with the referenced third-party kernel extension. For more information, please see the link below:
https://support.apple.com/HT210999
Blocking the messages
For a number of managed environments, these messages can be prevented from appearing. As long as a third-party kernel extension is whitelisted using an appropriate configuration profile, the message for it should not appear.
For more information about whitelisting kernel extensions using a configuration profile, please see the links below:
https://derflounder.wordpress.com/2018/04/12/whitelisting-third-party-kernel-extensions-using-profiles/
https://support.fleetsmith.com/hc/en-us/articles/360037495013-What-is-a-kernel-extension-
https://support.apple.com/guide/mdm/kernel-extension-policy-mdm88f99b98a/web