what version of airport utility should I download for windows 7 in order to set up airport extreme 802.11ac?
Apple has not provided a Windows version of AirPort Utility that can be used to configure one of the new "ac" wireless routers.
Use a Mac running Lion, Mountain Lion or Mavericks.....or an iPad or iPhone to set up the new router.
For more info, see System Requirements in this document:
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