Apple released AirPort Base Station Firmware Update 7.7.8 on Tuesday. The update fixes an issue that caused some AirPort Base Stations to disappear from AirPort Utility when Find My Mac is on. It’s specifically for AirPort Extreme and AirPort Time Capsule base stations with 802.11ac.
Apple also said there are security holes patched in the update, but the security document for this release has not been published as of this writing.
Apple’s patch notes in full:
AirPort Base Station Firmware Update 7.7.8 Information
Firmware update 7.7.8 is recommended for all AirPort Extreme and AirPort Time Capsule base stations with 802.11ac. This update addresses an issue that may prevent AirPort base stations from appearing in AirPort Utility when Back to My Mac is enabled.
You can download the update through AirPort Utility.