If the server cannot access the internet directly, you can manually download the necessary update packages from the Microsoft Update Catalog .

These are updated multiple times daily. You can find the latest standalone definition installers on the Microsoft Security Intelligence portal. Choose the version that matches your system architecture (usually 64-bit for Server 2016). 3. Command-Line and PowerShell Updates

For administrators who prefer automation or need to force an update, command-line tools are available. Microsoft Support

Search for "KB4052623" to find the latest antimalware platform update.

Select to download and install available Defender packages. 2. Manual Download from Microsoft Update Catalog

The most common method is to use the built-in Windows Update service, which automatically includes Defender's (definitions) and Platform Updates (KB4052623). Navigate to Settings > Update & Security > Windows Update .

Windows Defender on Windows Server 2016 (now officially ) can be updated through several methods, ranging from standard automatic updates to manual downloads for offline or air-gapped environments. 1. Automatic Updates via Windows Update