If you purchased Lion or Mountain Lion from the App Store in the past, you can install that version on another, previously erased boot volume, and use the following workaround to administer an 802.11b/g - only Express or Extreme after booting OS X Lion or ML.
Read the following caveats before proceeding:
- The procedure that follows applies to Lion and Mountain Lion systems only.
- AirPort Utility 5.6 will not run with Mavericks.
- This procedure will not restore AirPort Utility 5.6 to life with Mavericks.
- Be advised that using an older Express or Extreme may cause unknown problems when using Mavericks.
- The extent of such problems has yet to be determined.
- Remember that you are using obsolete equipment. Many new OS X features require supported AirPort equipment and support for 802.11b/g - only AirPort Base Stations is gone.
- Proceed at your own risk.
Lion / Mountain Lion's package installer will refuse to install superseded versions of AirPort Utility. Instead you will need to use a package extractor such as Pacifist or unpkg. Pacifist is shareware, unpkg is free.
Download Pacifist here: http://www.charlessoft.com/
Download unpkg here: http://www.timdoug.com/unpkg/
Download AirPort Utility 5.6 here: http://support.apple.com/kb/DL1482
When the AirPort Utility .dmg file finishes downloading, open it to expand and reveal the AirPortUtility56.pkg package installer file.
Directions for Pacifist (I do not have screenshots for unpkg but the idea is similar):
Open Pacifist and from its File menu, navigate to the package and open it.
Click the "reveal triangles" until you see AirPort Utility 5.6.app:
Select it and then click Install from Pacifist's toolbar. It will then be installed in your Utilities folder, and you can quit Pacifist.