It wasn't flashy. It didn't add new features. But it quietly fixed a dozen systemic performance cancers that made Windows 7 and 8.1 feel "broken" after years of security patches.
Essentially, it is a service-stack update designed to fix the "plumbing" of the Windows Update mechanism itself. Key Purposes of KB4023814:
If the update is stuck in a loop, you may need to reset the Windows Update components. Open . Run the following commands: net stop wuauserv net stop bits
Microsoft documented specific known issues regarding the installation of this update during its release lifecycle: