April 10, 2018—KB4093115 (Security-only update)

Applies to: Windows 8.1Windows Server 2012 R2

Improvements and fixes


This security update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

  • Windows Update and WSUS will offer this update to applicable Windows client and server operating systems regardless of the existence or value of the "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\QualityCompat\cadca5fe-87d3-4b96-b7fb-a231484277cc" registry setting. This change has been made to protect user data. 
  • Security updates to Internet Explorer, Microsoft scripting engine, Microsoft graphics component, Windows Server, Windows kernel, Windows datacenter networking, Windows Hyper-V, Windows virtualization and kernel , and Windows app platform and frameworks.

For more information about the resolved security vulnerabilities, see the Security Update Guide.

Known issues in this update


Microsoft is not currently aware of any issues with this update.

How to get this update


This update is now available for installation through WSUS. To get the standalone package for this update, go to the Microsoft Update Catalog website.

File information

For a list of the files that are provided in this update, download the file information for update 4093115