The phrase "patch level" refers to the specific version or update of a software or system. It shows how up-to-date the software is with the latest fixes and improvements. Full definition
Other than the updated security patch level, the new update also comes with performance improvements and bug fixes, which is normal for all monthly security updates. (nashvillechatterclass.com)
The update screen now lists the Android version and security patch level. (9to5google.com)
Powered by Linux kernel 3.10.84, the update reportedly includes the Android security patch level of February 1, 2018. (news.softpedia.com)