diff --git a/windows/security/threat-protection/windows-defender-atp/onboard-downlevel-windows-defender-advanced-threat-protection.md b/windows/security/threat-protection/windows-defender-atp/onboard-downlevel-windows-defender-advanced-threat-protection.md
index 677d282889..170be8e9ca 100644
--- a/windows/security/threat-protection/windows-defender-atp/onboard-downlevel-windows-defender-advanced-threat-protection.md
+++ b/windows/security/threat-protection/windows-defender-atp/onboard-downlevel-windows-defender-advanced-threat-protection.md
@@ -19,6 +19,7 @@ ms.date: 06/17/2018
 
 - Windows 7 SP1 Enterprise
 - Windows 7 SP1 Pro
+- Windows 8.1
 - Windows Defender Advanced Threat Protection (Windows Defender ATP)
 
 [!include[Prerelease information](prerelease.md)]