May I know if you are using this AP as stand alone or connecting to a ZD?
If it is an stand alone AP, you can use the most latest supported version 22.214.171.124.500
. If you are connecting this to ZD, then ZD will push the firmware automatically.
Let me know the scenario and I will try to help.
Just to let you know, 126.96.36.199.11 stand alone image is not available in support portal, only ZD image is available which you cannot upload to AP directly.
Syamantak Omer | Community moderator | Staff TSE | CWNA | CCNA | RASZA | RICXI | Follow me at https://linkedin.com/in/syamantak-omer-5949b6124