iCloud for Windows version 7.8.1 is now available for download at Apple support site, supported Windows 7 or later which resolved synching shared album issue happen in iCloud due to incompatibility with Windows 10 October 2018 Update (V1809).
The support page of iCloud for Windows has now been revised to reflect that iCloud for Windows should work fine on the latest version of Windows 10 Update.
Cloud for Windows 7.8.1 requires Microsoft Windows 7 or later; Outlook 2007 or later or iCloud.com (for Mail, Contacts, Calendar); and Internet Explorer 10 or later, Firefox 30 or later, or Google Chrome 28 or later (for Bookmarks).
Earlier this month, iCloud for Windows 7.7.027 reported incompatible with Windows 10 October 2018 Update (V1809). When users trying to install iCloud for Windows version 188.8.131.52 on Windows 10 October 2018 Update version 1809, an error message this version of iCloud for Windows is not supported display and installation will fails.
Microsoft has blocked iCloud users from upgrading to the latest version of Windows if iCloud for Windows is installed because users may experience problems when updating the synchronization of shared albums after upgrade to Windows 10 version 1809. Those trying to do a fresh install of iCloud after updating Windows ran into error messages.
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mspoweruser: iCloud now supports Windows 10 October 2018 Update
appleinsider: iCloud for Windows updates to fix critical issues with Windows 10 October update