Apple and Microsoft are working together on a fix.
If users try to install the latest version of iCloud for Windows 10, version 7.7.0.27 with the October 2018 Update already installed, an error message appears saying that “iCloud for Windows requires Windows 7, Windows 8, or Windows 10 (April 2018 Update) and earlier.”
If you have the app already installed, then you may find there are several issues when using the software to sync your files and photos with Apple’s cloud storage service.
Source: Windows 10 October 2018 Update has broken iCloud | TechRadar