Windows 10 Technical Preview has been updated to build 9860 for the people who signed up to the Windows Insider Program. Microsoft has added Action Center to Windows 10, which will handle your notifications and alerts from both Modern and traditional Windows applications from the system tray. There are almost 7,000 changes in the new build and the download size is around 2 GB.
You can wait for the update to arrive for your PC or you can start the download right now by going to "PC Settings", "Update and Recovery" and then clicking on "Preview Builds." Windows 10 will check to see if there is any update available and prompt to "Download Now."
Source: Blogging Windows