If you recently upgraded to macOS Catalina 10.15.4, you might see a kernel extension warning. This is because Apple doesn’t recommend it in macOS 10.16.
The message refers to “legacy extensions” and states that they are “not as secure or reliable as modern alternatives”. Apple will replace it with one Endpoint security framework. In one Support page Apple calls the change:
In 2019, Apple informed developers that macOS Catalina will be the last macOS to fully support older system upgrades, and we worked with developers to transfer their software. In addition to these enhancements, developers are helping developers modernize the Mac, improve security and reliability, and enable more user-friendly software distribution methods. No final transition date has yet been set.
This decision aims to increase user security because Vein is a sensitive part of the operating system that controls everything else. It’s a good thing to keep third-party applications out of this area.