Late Tuesday night, Apple leased version 7.4.2 of its firmware for its 802.11n-based AirPort Extreme and Time Capsule routers. The revised firmware, which can be downloaded here or the update application within the AirPort Utility program, makes the following fixes and changes:

• Fixes some problems with extending and maintaining connectivity with extended networks.
• Fixes an issue with clients that enable 802.11 “Power Save.
• Fixes connectivity issues with some third-party devices.
• Fixes an issue when the base station is configured for PPPoE.
• Fixes some Back To My Mac issues with connectivity and support for third-party routers.
• It is recommended that AirPort Utility 5.4.2 or later be installed before upgrading to Firmware version 7.4.2.

The update requires Mac OS X 10.4 or later to install and run.