https://blog.0patch.com/2021/05/0patch-security-adopts-windows-10-v1809.html
The May 2021 Windows Updates will contain the last official security fixes for many editions of three Windows 10 operating system versions:
Windows 10 v1803
Windows 10 v1809
Windows 10 v1909…And so we’ve decided to security-adopt Windows 10 v1809 (build 10.0.17763) – as we have previously security-adopted Windows 7, Windows Server 2008 R2, and Office 2010.
Starting this month, initially for one year, we will actively gather information about vulnerabilities affecting Windows 10 v1809 and, based on our risk criteria, create micropatches for this operating system. We will be particularly interested in any vulnerabilities patched by Microsoft in still-supported Windows 10 versions, and whether they might affect v1809 as well…In order to have our Windows 10 v1809 micropatches applied, users will have to have their computers fully updated with the latest (May 2021) official Windows Updates provided by Microsoft…