Active Directory Functional Level Support

The supportability of Active Directory (AD) functional levels, such as Windows Server 2008 R2 and Windows Server 2012 R2, depends on the lifecycle policy of the Windows Server operating system version they are associated with. Here’s a clear explanation

• Functional Levels and OS Support:
  • AD functional levels are tied to the features and capabilities of the corresponding Windows Server OS.
  • Once the support lifecycle for a Windows Server OS ends, Microsoft no longer officially supports the associated functional levels.
• Windows Server Lifecycle:
  • Windows Server 2008 R2: End of extended support was January 14, 2020.
  • Windows Server 2012 R2: End of extended support was October 10, 2023.
  Since these OS versions are no longer supported, functional levels tied to them are also not supported in terms of security updates, bug fixes, or new features.
• Upgrading AD Functional Levels:
  • It’s strongly recommended to upgrade the AD functional level to at least 2016 or higher to align with supported Windows Server versions.
  • Functional level upgrades enable modern AD features and enhanced security.

• What Does "Not Supported" Mean?

  • You can still use AD at 2008 R2 or 2012 R2 functional levels, and your environment will function.
  • However:
    • Microsoft will not provide updates or patches for issues specific to deprecated functional levels.
    • Any issues or vulnerabilities that arise in these environments will not be addressed.
•