The update contains the usual improvements and bug fixes, but Apple mentions three specific changes:
- The ability to extend the Guest Wi-Fi network on a network that is configured with multiple AirPort Base StationsThe update weighs in at 20.64MB and is available through Apple's software update website.
- The ability to add a WPS-capable Wi-Fi printer
- Improved international support
Update: Apple has also released AirPort Base Station and Time Capsule Firmware Update 7.6.3 for updating the units themselves.
Finally, the AirPort Utility app for iOS has also been updated to add the new functionality.