Image courtesy of The Verge
Microsoft has officially sided with those who believe sentences should have one space instead of two. Microsoft Word is being updated to support this change, meaning if you still use double spaces after a period, it will appear as an error, and the recommended change will be a single space. The company started testing this change on the desktop version of the app. And like other Editor suggestions, you have the option to ignore it once, make the change, or turn it off. The change is rolling out to all desktop users of the app soon.
Source: The Verge