They're getting an app switcher to bring them more in line with the Nokia X2. This allows you to easily switch or close apps. Just swipe down from the top of the screen, tap the app switcher icon and then tap the app you want to switch to or tap the 'x' icon to close it.
The update also includes improvements to the Nokia Store, integrating third party app stores so you can manage all of your apps in one place, as well as making it easier to find and download apps and games.
Plus the store is getting a new home screen Spotlight widget to help with app discovery and adding support for one-click downloads so you can get apps faster.
Last but not least the update adds Outlook.com, OneNote and One Drive if you haven't already downloaded them.
The new software has already started rolling out as an over-the-air update. You should automatically be notified when it's available but you can also manually check for it from the settings screen by heading into 'About phone' then 'System updates'.