I don’t think there is anything else you need to change.
As a sanity check: you can change the pin definition back to 15, recompile and run the firmware. When it sends a signal, you should hear the relay making a noise. If not, I suspect the 16-digit HEX code you entered is not right — the firmware will detect if it’s a valid code, so if it’s not exactly 16-digit long, or if any character is not a hex code, it will not recognize it as a valid RF code.