This Windows 10 feature update brings very few new policy settings. At this point, no new 21H1 policy settings meet the criteria for inclusion in the security baseline. We are, however, refreshing the package to ensure the latest content is available to you. The refresh contains an updated administrative template for SecGuide.admx/l (that we released with Microsoft 365 Apps for Enterprise baseline), new spreadsheets, .PolicyRules file, along with a script change (commented out the Windows Server options in the Baseline-LocalInstall.ps1 script)
Windows 10, version 21H1 is a client only release. Windows Server, version 20H2 is the current Windows Server Semi-Annual Channel release and per our lifecycle policy is supported until May 10, 2022.