Hi ,
There is a mismatch between
https://documentation.meraki.com/Architectures_and_Best_Practices/Cisco_Meraki_Best_Practice_Design/...
Note: RX-SOP is available only on Meraki 802.11 ac Wave 2 APs (MR30H/33/42/42E52/3/53E/74/84)
and
https://documentation.meraki.com/MR/Radio_Settings/Receive_Start_of_Packet_(RX-SOP)
RX-SOP is only supported on 802.11 ac Wave 2 and 802.11 ax APs i.e. MR30H/33/42/52/53/74/84/42E/53E/45/55 starting firmware version MR25.x
🙂