Installing Endpoint Protection on macOS 10.15.4/10.16 results in a 'Legacy System Extension' warning.
Article ID: 186024
Installation of Symantec Endpoint Protection (SEP) for Mac on a pre-10.15.4 macOS system, which is then upgraded to 10.15.4 or newer will prompt the end-user with a warning message about a Legacy System Extension that will be incompatible in future releases of macOS.
Apple is dropping kernel extension support in 10.16.
End-users will want to click 'OK' on the warning prompt. This is expected behavior with 14.2 RU2 and 14.2 RU2 MP1 releases due to Apple dropping kernel extension support in 10.16.