RAISE FOREST FUNCTIONAL LEVEL AND DOMAIN LEVEL IN ACTIVE DIRECTORY

Possible to set the domain functional level to a value that is higher than the forest functional level, but cannot set the domain functional level to a value that is lower than the forest functional level.

Functional levelNew featuresSupported Windows Server version for DC
Windows Server 2000Windows Server 2000 – 2008 R2
Windows Server 2003Forest trustWindows Server 2003 – 2016
Domain rename
Read Only Domain Controller (RODC)
Domain-based DFS with access-based enumeration support
Windows Server 2008DFS replication for SYSVOL instead FRSWindows Server 2008 – 2022
Fine-grained password policies
Windows Server 2008 R2Active Directory Recycle BinWindows Server 2008 R2 – 2022
Managed Service Accounts
Windows Server 2012KDC support for claims, compound authenticationWindows Server 2012 – 2022
Windows Server 2012 R2Protected UsersWindows Server 2012 R2 – 2022
Authentication Policies
Windows Server 2016Privileged access management with MIMWindows Server 2016 – 2022
Smart card required for interactive logon

Note: Windows Server 2016 is the maximum functional level for Active Directory.

Powershell cmd to check the current DFL and FFL

Get-ADDomain | fl Name, DomainMode
Get-ADForest | fl Name, ForestMode

https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels?source=recommendations#windows-server-2016-functional-levels