'This version of AirPort Utility doesn't support this base station.'

Easier if you have an windows pc around you. You can install an older Airport Utility for Windows on it and configure your device.

http://www.withsteps.com/3824/this-version-of-airport-utility-doesnt-support-thi s-base-station-solved.html

After you were able to configure it ... it works great with new versions of macOS or iOS.

Version 6.x of the AirPort Utility does NOT support the 802.11g AirPorts. In order to administer these older base stations you will need to use version 5.6. Unfortunately, it will not install under OS X Mountain Lion ... at least not without using a workaround.

Here are the basic steps to install version 5.6 under Mountain Lion using CharlesSoft's Pacifist:

1. If you haven't already download the AirPort Utility disk image file directly from Apple Support Download
2. Place the resultant AirPortUtility56.dmg file onto your Mac's Desktop.
3. Run Pacifist.
4. Click on the Open Package option. Find the disk image file that you just placed on your desktop, and then, click on Open.
5. The utility is located as follows: Contents of AirPortUtility56.dmg > Contents of AirPortUtility56.pkg > Contents of AirPortUtility56Lion.pkg > Applications > Utilities > AirPort Utility 5.6.app
6. Drag AirPort Utility 5.6.app to your Mac's /Applications/Utilities folder.

You can now run the AirPort Utility from the Utilities folder.

Thank you, this is exactly the problem I had and you have solved it for me in a quick and easy to follow series of steps.