I have need to setup my Mac with Windows recently. For email I installed Outlook with my Office365 license. I discover various options, one that in my case was missing a way to "confirm delivery receipt and read receipt". So using the same email account, iCloud, on Windows I can use that option and not non the Mac! Support tell me the Mac version require a Exchange Account! And that the Mac version is a new software, release 15.36.1 (170721).