Microsoft encourages users to adopt the latest version of Windows or a version eligible for monthly security updates to protect against security threats. Older Windows ISOs are vulnerable due to outdated security updates and antimalware software. Microsoft has released an update for Microsoft Defender to enhance the security of these older Windows images. This update includes the latest Microsoft Defender binaries, which must be applied offline to WIM and VHD files for Windows 11, Windows 10 (Enterprise, Pro, Home), Windows Server 2022, 2019, and 2016. The update improves both the anti-malware client and engine, with package sizes of 78.2 MB for ARM64, 128 MB for x86, and 132 MB for x64 systems. Users need a 64-bit version of Windows 10 or later, PowerShell 5.1 or later, and specific modules to implement the update. Regular updates every three months are recommended for optimal security.