how can i get back to the old version of ios? to ios 13.4

Due to my clumsy operation, I purchased mobile gamepad to help me control the game better. But since upgrading to 13.4, my gamepad can't work. I went to the gamepad manufacturer and knew that a bug in the data interface of 13.4 caused the gamepad to stop work. Please fix the bug as soon as possible so that our millions of gamepad players can play better games and charge without any doubt. thank you very much!

Yes yes because I am gamer player

why do you say that?

I contacted Apple and am waiting for a response

thank you for your feedback