For those using Apple's AirPort Wi-Fi base stations, Apple has issued a firmware update that fixes a few bugs involving Time Machine, IPv6, and Wi-Fi connectivity.
Apple's AirPort base stations are its solution for Wi-Fi connectivity, providing not only network and Internet access, but also hosting NAS for Time Machine backups. With some of its models, using the high-speed 802.11n protocol resulted in some problems with IPv6 tunneling, which may interfere with online services such as iCloud's Back to My Mac feature. In addition, the update fixes some loss in connectivity for iOS devices, and a problem with Time Capsule connectivity in which the backup disk may be erroneously reported as being in use.
While Apple does not specify which models of AirPort base stations this update is for, it does state it applies to any AirPort base stations with 802.11n capability, which includes most that shipped from 2007 onward. However, those between 2007 and 2009 were shipped with Draft-N capability, and this update may not apply to them.
Unlike other updates from Apple, this one is not available through its standard OS X software update services, and instead requires you to use Apple's AirPort Utility to update your configured AirPort devices. This can be done simply by selecting your AirPort device and clicking the Update button.
Like other updates for Apple products, this firmware update cannot be uninstalled once applied; however, if you do run into problems with the update then you can try to manually downgrade to a prior version, which will take a few steps but should be doable.