Customizable toolbar- The new toolbar highlights your most commonly used commands and is fully customizable.My Day - A new addition that gives you a view of your agenda or calendar events right from your main mailbox and includes a 2-week calendar view that gives you a quick overview of your upcoming events.New features for composing emails and events-Completely new features for composing emails and events that improve your productivity through improvements such as an easily accessible formatting bar, suggested times, and locations.Search Improvements - Search is now created with the same engine that is used for other Office 365 experiences, so you can quickly find exactly what you're looking for.Improved synchronization - Based on Microsoft's sync technology, which also supports Outlook Mobile, the new Outlook for Mac syncs your messages with improved speed and reliability.Note that it has been translated using Microsoft Translate:

Below is the changelog shared by Windows United.