Nokia Changelog says that the new version includes Update Settings UI, Screen and Pedometer card, Enhance Power saving and background activity manager, Enhance Low Light Camera Image Quality, Nokia Cloud, Notification wake up, and long screen capture.
The update is already rolling out to the users of Nokia 6 in phases. If you did not receive the update wait for few days or try checking for it manually by heading over to system updates section in the Settings app. Make sure you've at least 50 percent juice left on your phone before updating it.