Microsoft website says about Cloud Files API (Cloud Sync Engines):
Starting in Windows 10, version 1709, Windows provides the cloud files API.
However, OneDrive that is built using this API can run on earlier Windows versions, including Windows 8.1. I guess that I just need to install all Windows updates or need to install some windows components on Windows 8.1.
Is Cloud Files API supported on Windows 8.1?
I have tested OneDrive on Win 8.1 x64 Version 6.3 (Build 9600)
And OneDrive on Win 10 x64 Version 1909 (Build 18363.1082)
Windows 8.1 does not support offline files in the manner Windows 10 is doing. It just synchronizes all files from the server to the client.
I have also tried calling cloud filter API - it is not supported on Windows 8.1
Unhandled exception. System.TypeLoadException: Could not find Windows Runtime type 'Windows.Storage.Provider.StorageProviderSyncRootManager'