Microsoft had recently released new Defender anti-malware update package for Windows OS installation images, ie, for Windows Imaging Format (WIM) and VHD (Virtual Hard Disk) formats. The new definitions support Windows 11, all editions of Windows 10, Windows Servers 2016 and 2019. This update package is necessary as a Windows installation image may contain old, outdated anti-malware definitions and software binaries. Aside from better security, these updates can also provide improved performance benefits too in some cases.

Microsoft is delivering the latest security definitions for Windows images via security intelligence update version 1.385.1537.0. The Defender package version is 20230330.2. On the support document describing the the new update, Microsoft writes:


From Microsoft's security bulletin, we learn that the security intelligence update version 1.385.1537.0 was released at the end of last month. It adds threat detections for various trojans, hacktools, ransomware, among others. For those wondering, the latest intelligence update is version 1.387.1114.0 at the time of writing.