It’s just a minor update at this point, as you would only find some of the Fluent Design implementation along with a few interface tweaks.
Reveal highlight
In this preview you’ll quickly notice Reveal highlight as you hover over items in the app. Reveal highlight is an interactive visualization that brings illumination to help you navigate and interact with an app. In other words, this Fluent Design element helps to show hidden borders and to use light to make it easier to discover and learn how to use elements.
Acrylic material
Microsoft also seems to be adding Acrylic material, which is another element of the Fluent Design System that brings light and colors from the desktop illuminating the app surface from behind using transparency, blur, and noise texture overlays.
Interface tweaks
In addition, these new apps have some interface design tweaks. For example, in the update, you can clearly see that the app header is no longer present. Instead, the app interface uses the entire real estate of the window. You still get the app name in the top-left corner and the minimize, maximize, and close buttons in the top-right corner, but the boring bar with a solid color is no longer part of the experience. The left pane has also been slightly modified, so that it’s clearer to identify which account and folder you’re looking at using a white border on the left. These changes are now appearing for some users in the Windows Insider Program testing previews of the Windows 10 version 1803, which could indicate that these design updates may be planned to roll out next year, but Microsoft could well release the new changes before that happens. If you’re running the latest preview of Windows 10, you can check if your Mail and Calendar apps include Microsoft Fluent Design System by installing the latest update from the Store. Then go to Mail settings > Personalization, and make sure to turn off the background feature. What do you think about the improvements with Mail and Calendar apps? Tell us in the comments. Update November 3, 2017: Mail and Calendar with Fluent Design are now available to everyone, including those running the version 1803 (preview), 1709, and 1703. All content on this site is provided with no warranties, express or implied. Use any information at your own risk. Always backup of your device and files before making any changes. Privacy policy info.