Firmware update 7.7.3 is recommended for all AirPort Extreme and AirPort Time Capsule base stations with 802.11ac.
It provides security improvements related to SSL/TLS. Other AirPort base stations do not require this firmware update.
AirPort Extreme and AirPort Time Capsule with 802.11ac (June 2013)
Note: After updating the firmware, some users may need to re-enable Back to My Mac on their AirPort base stations using AirPort Utility and on their Macs using System Preferences.
How to re-enable Back to My Mac on AirPort base stations:
From the menu bar, select Go > Utilities and double-click AirPort Utility.2.
Select the AirPort base station that is configured with Back to My Mac and click Edit.3.
If prompted, enter the base station password. 4.
In the Base Station tab, select the Back to My Mac account you want to re-enable and click Edit.5.
Enter your Apple ID password and click Sign In.
A green status indicator will appear indicating a successful authentication.6.
Click Update to save the changes.
How to re-enable Back to My Mac on your Mac computer:
1. On each computer you use with Back to My Mac, choose Apple menu > System Preferences, then click iCloud.
2. In iCloud preferences, deselect Back to My Mac, then select it again.