About AirPort Utility 6.3 for Mac
Use AirPort Utility to set up and manage your 802.11n and 802.11ac AirPort base stations, including AirPort Express, Extreme, and Time Capsule. AirPort Utility 6.3 allows you to configure and manage the new AirPort Extreme and AirPort Time Capsule with 802.11ac Wi-Fi, and includes enhanced remote management capabilities.
You can get the update by selecting Software Update from the Apple menu at the top left of your screen or by clicking the link below.
Recently, Apple also updated its AirPort Utility app for iOS.