If you recently upgraded to macOS Catalina 10.15.4, you may have seen a warning message regarding kernel extensions. This is because Apple does not recommend them in macOS 10.16.
The message refers to “legacy system extensions” and says that they are “not as secure or reliable as modern alternatives.” Apple will replace them with one Endpoint security framework. In a support page Apple calls the change:
In 2019, Apple informed developers that macOS Catalina will be the last macOS to fully support older system extensions, and we’ve worked with developers to transfer their software. By going beyond these extensions, developers help further modernize the Mac, improve security and reliability, and enable more user-friendly software distribution methods. No definitive transition date has yet been set.
This decision aims to increase the safety of users because core is a sensitive part of the operating system that controls everything else. It is a good thing to keep third party applications out of this area.