Mitel had this information on the subject for me.    Mitel direct from ascom. Problem with 802.11h "power constraint" IE Components: All Products Background: When the Power constraint IE is present and when the device is configured for reg domain US the device defaults to 0dBm Tx power. (Most likely happens to all modes except "world mode") This is especially a problem with Aerohive and Meraki as this IE is present by default and cannot be removed. With Cisco this IE only appears when DTPC is unchecked and local power constraint is configured under Wireless>>802.11a/n/ac>>802.11h in the WLC. Other platforms impact unknown at the moment. Due to FCC regulations reg domain "world mode" is no longer allowed as only source to determine geographic location. Meaning using "World mode" is not a solution. See IEEE 802.11h section 7.3.2.15 for details Solution: Corrected the transmit power setting for regulatory domains when "World mode (802.11d)" is not used.     ... View more