[Stefan]

i installed pilight v8.1.5-nightly-38458d69 and wiringPi 2.52 on my Raspberry PI 4 / Buster. The installation worked according to the instructions with no errors. 
If i switch with command pilight-send -p kaku_switch -i... nothing happens, also the pilight-receive command is not working. If i put this SD-Card in my PI3B+ everything works, sending and receiving. I use the same receiver and send-modul.

Code:

{
    "devices": {
        "Switch1": {
            "protocol": [ "kaku_switch" ],
            "id": [{
                "id": 16657026,
                "unit": 0
            }],
            "state": "off"
        },
        "Switch2": {
            "protocol": [ "kaku_switch" ],
            "id": [{
                "id": 16657026,
                "unit": 1
            }],
            "state": "off"
        }
    },
    "rules": {},
    "gui": {
        "Switch1": {
            "name": "Switch Nr 1",
            "group": [ "MeineSwitches" ],
            "media": [ "all" ]
        },
        "Switch2": {
            "name": "Switch Nr 2",
            "group": [ "MeineSwitches" ],
            "media": [ "all" ]
        }
    },
    "settings": {
        "log-level": 6,
        "pid-file": "/var/run/pilight.pid",
        "log-file": "/var/log/pilight.log",
        "standalone": 0,
        "webserver-enable": 1,
        "webserver-root": "/usr/local/share/pilight/webgui",
        "webserver-http-port": 5001,
        "webserver-https-port": 5002,
        "webserver-cache": 1,
        "whitelist": "",
        "gpio-platform": "raspberrypi3"
    },
    "hardware": {
        "433gpio": {
            "sender": 0,
            "receiver": 1
        }
    },
    "registry": {
        "webserver": {
            "ssl": {
                "certificate": {
                    "location": "/etc/pilight/pilight.pem"
                }
            }
        },
        "pilight": {
            "version": {
                "current": "8.1.5"
            }
        },
        "hardware": {
            "RF433": {
                "mingaplen": 4420,
                "maxgaplen": 72900,
                "minrawlen": 26,
                "maxrawlen": 400
            }
        }
    }
}

I attached my config.json. is maybe gpio-platform wrong? Thank you for your help.

[curlymo]

What could possibly be the first clue when running on a raspberry pi 4 and having raspberry pi 3 configured?!

[Stefan]

omg, i only looked at the supported GPIO platforms (on Configruation - Settings) and missed to try out raspberrypi4. now it worked fine. thank you!