Winphollowers has posted some leaked screenshots from an internal Microsoft PowerPoint presentation, which show off Windows Phone 8.1's heavily improved Notification Center.
The Notification Center, or "Action Center" as Microsoft seems to call it, will display itself with a quick swipe from the top of the screen. From here, four basic settings are on-hand, Wi-Fi, Bluetooth, and more. These four actions are customizable, so you can play around with them, but the basic Action Center will also display the date, and battery level percentage.
If you continue to pull on the Notification Center, a full "Action Center" will be displayed with even more information and settings. Microsoft's update to its mobile OS will also push forward a split in volume controls for ringer/notifications and media/apps, too. Windows Phone 8.1 will also bring forth Microsoft's own personal assistant, "Cortana". We should hear more about Windows Phone 8.1 at Microsoft's Build developer conference in April.