TechPowerUp posted a review on the User Patch Unlocks Windows 7 and 8.1 Updates for Core Kaby Lake and Ryzen A quote from the article:

Microsoft, in a bid to ensure users of 7th generation Intel Core "Kaby Lake," AMD A-series "Bristol Ridge," and AMD Ryzen "Summit Ridge" processors stick to Windows 10, ensured that the three platforms don't receive software updates when running older Windows 8.1 or Windows 7 operating systems. A new user-made patch removes this draconian restriction, letting you install Windows 7 or Windows 8.1 on your new-generation CPU powered machine, and receive regular software updates through Windows Update.

The patch is open-source, so you can inspect its code, and available on GitHub. The author of the patch, Zeffy, discovered two new functions to system file wuaueng.dll after the March 2017 update for Windows 7 and Windows 8.1, labeled "IsCPUSupported(void)" and "IsDeviceServiceable(void)." This library is patched to toggle those two functions "1," telling Windows Update that the CPU is "supported" and that the platform is "serviceable," making it eligible to receive updates.

 User Patch Unlocks Windows 7 and 8.1 Updates for Core Kaby Lake and Ryzen @ techPowerUp