Dear @Foppe,

I believe this is a severely under-documented "feature". This toggle is presented under the QOS header which is entirely inappropriate. Moreover, the way it s described it reads as some kind of multi media QOS function but in reality, it is a "legacy wifi protocol toggle" which, if not selected, reduces the wifi troughput to almost nothing in modern terms. This is not clear at all from the way it is described and presented.

So you are configuring the EAP via web UI in Standalone mode (without Omada Controller), right?

There is a related Note given in the UG of the EAP you may not notice (in the first sentence at Page 45): 

If 802.11n only mode is selected in 2.4GHz (or 802.11n only, 802.11ac only, or 802.11 n/ac mixed mode selected in 5GHz), the WMM should be enabled. If WMM is disabled, the 802.11n only mode cannot be selected in 2.4GHz (or 802.11n only, 802.11ac only, or 802.11 n/ac mixed mode in 5GHz).

Could this please be better defined / described in future firmwares, and be moved away from under the QOS header in the configuration tab? I believe this would save a lot of people a lot of headache and frustration :-)

I don't think it is surprising that the WMM setting is under Wireless > QoS, however. This is not a special design on TP-Link APs.

Quote the definition of WMM from Wikipedia for reference:

"Wi-Fi Multimedia (WMM), is a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic Quality of service (QoS) features to IEEE 802.11 networks."

Dear @Foppe,

Thanks for answering. I am configuring the AP's in my OC200 controller software, whith separate SSID's for 2.4 and 5 ghz.

While it might be that technically, this is a QOS feature, you might consider explaining the consequences of selecting/deselecting this feature under the "i" information text that you provide for this toggle, and in your faq about optimizing wifi performance

Welcome and thank you for the valued suggestion, I've written it down for future evaluation.