The latest Mac OS is 10.15.2 (Catalina), released Tuesday, December 10th, 2019. If you have upgraded to 10.15 or 10.15.1 already, get the 10.15.2 update. (Remember that 10.15 is a significant upgrade and you should be sure that your apps are ready for it.) See this article for information about compatibility with 10.15. Also see Apple’s release notes for macOS 10.15.2— they’re extensive.