If you're an Office Insider with a Mac on the Fast ring, a new build of Office 2016 is available for you. The version number is 15.36 (170524).
The changelog doesn't include anything in the way of front-facing features, but as you'd expect, there are a number of bug fixes:
Google accounts: Non-supported folder actions and Follow Up options are now hidden instead of appearing as disabled
Templates: New icon for saved templates (.emltpl extension)
Delegates can now add Skype for Business online meeting details when scheduling events on behalf of principals
After a delegate accepts a meeting invitation on behalf of a principal, the event will now show as Busy instead of Tentative
Preferences to automatically sign and encrypt outgoing messages are now respected when using Resend
Decrease and increase indent actions in the Format menu now work properly for numbered lists
Position of the separator between the calendar sidebar and the mini calendar is now maintained
There is also one known issue:
- Certificate for outlook.office365.com keeps prompting intermittently
- This issue is being actively investigated; stayed tuned for updates
If you're on the Slow ring instead, you should also have seen some new features recently, mainly in Outlook 2016. These include Read & Delivery Receipts, and Drag & Drop Emails to Create New Items.
In order to jump on the Office Insider Program, you need to be a paid Office 365 subscriber. Once you are, you can open any Office application, and go to Help -> Check for updates, where you'll find the option to begin receiving pre-release builds.