Microsoft is rolling out the next build update to the "Fast" ring of the Windows Insider Program - Build 9879. This latest build has many changes, some new features, but also a few gotchas to be aware of. If you are new to the Windows Insider Program, this new build will come to you automatically via Windows Update. If you're currently in the Fast ring, the build is available now. If you're in the Slow ring, you won't receive the build right away, Microsoft says.

The update may occupy 20GB or more of your disk space due to driver install duplication.Among the changes in the new build are the following:

• With 9879 you can now hide the Search or Task View buttons on the taskbar. Just right-click on the taskbar and uncheck the check boxes for whichever button you want to hide.
• Updated minimize and restore animations for apps.
• Stability issues
• You can now use Snap Assist when snapping apps across multiple monitors. Microsoft also introduced new 3 finger gestures for precision touchpads. Here is the list of the new 3 finger gestures for you to try:
  • 3 finger up -> Task View
  • 3 finger down -> Show Desktop
  • 3 finger flick to left or right -> switches to previous app (go back 1)
  • 3 finger move left or right -> Alt-Tab (Task View) pops up and you can select the app you want (remove fingers to select)
  • 3 finger tap -> Search
• OneDrive will use selective sync. This means you choose what you want synced to your PC and it will be. What you see is really there and you don?t need to worry about downloading it. You can choose to have all of your OneDrive files synced to your PC, or just the ones you select.
• One easy way to get to OneDrive files – through File Explorer. To manage OneDrive, right-click on the OneDrive icon in the notification area and click "Settings" to manage how OneDrive behaves. You'll be able to adjust things like auto save, choose which folders are synced offline, and more.
• Microsoft's new interoperability focused Edge rendering engine (Internet Explorer) is enabled for 10% of Windows Insiders, in order to offer feedback
• You can now play MKV files directly from Windows Media Player (as well as other desktop and modern apps), MKV files will show thumbnails and metadata in File Explorer, support for DLNA and Play To scenarios has been added, and more.
• Added support for H.265 HEVC.
• UI refinements:
  • In File Explorer, you can now pin your favorite folders to Home.
  • Modern dialogs are now correctly windowed.
  • Eagle-eyed Windows Insiders will also notice a few new icons.
• New Insider Hub app. The Insider Hub includes all the latest news and announcements regarding the Windows Insider Program.
• Windows Feedback app:
  • You can now sort feedback entries based on trending topics, number of Me Too, and most recent.
  • When you're finished adding feedback, the Windows Feedback app will take you back to the category you were already in, not the list.
  • Fixed an issue when you tried searching for existing feedback it would give you an error and no filter anything at all.
  • Screenshot button now easier to find
• ISO images of the new build comin glater, at the same time as Microsoft publishes to the Slow ring.