iOS 7.1

Apple recently released iOS 7.1 which refines the iOS 7 experience, and sorts some issues, including AirPlay dropping out.  Read more about the update here:

If you are using Apple Configurator, you can easily update your iPads in the 'Supervise' section, by selecting the iPads you wish to update and changing the 'Update iOS' pop-up menu to 'When Update is Available' and clicking 'Apply' down the bottom of the window.