To find out which version of Outlook is installed locally on your Windows computer, do the following:

1. In Outlook, click File.
2. Click Office Account (or "Help" if you don't see Office Account).
3. Under Product Information, locate the version and build number.

To find out which version of Outlook is installed locally on your Mac computer, do the following:

1. Open Outlook.
2. On your menu bar, click Outlook (next to the Apple logo). If it's hidden, hover over the top section of the screen to show the menu bar.
3. Click About Outlook to see the version information.

Yesware for Outlook will only work on Mac 2016 or later for users with an Office 365 mail server.