Activate / Deactivate Comfort Heating

[JörgWende]

I want to control my heating and found the following API Call: 

{
"apiVersion": 1,
"commands": {
"activate": {
"isExecutable": false,
"name": "activate",
"params": {
"temperature": {
"constraints": {
"max": 37,
"min": 3,
"stepping": 1
},
"required": false,
"type": "number"
}
},
"uri": "https://api.viessmann.com/iot/v1/equipment/installations/2054585/gateways/7736172033094220/devices/0..."
},
"deactivate": {
"isExecutable": false,
"name": "deactivate",
"params": {
},
"uri": "https://api.viessmann.com/iot/v1/equipment/installations/2054585/gateways/7736172033094220/devices/0..."
},
"setTemperature": {
"isExecutable": true,
"name": "setTemperature",
"params": {
"targetTemperature": {
"constraints": {
"max": 37,
"min": 3,
"stepping": 1
},
"required": true,
"type": "number"
}
},
"uri": "https://api.viessmann.com/iot/v1/equipment/installations/2054585/gateways/7736172033094220/devices/0..."
}
},
"deviceId": "0",
"feature": "heating.circuits.0.operating.programs.comfortHeating",
"gatewayId": "7736172033094220",
"isEnabled": true,
"isReady": true,
"properties": {
"active": {
"type": "boolean",
"value": false
},
"demand": {
"type": "string",
"value": "heating"
},
"temperature": {
"type": "number",
"unit": "celsius",
"value": 23
}
},
"timestamp": "2023-02-02T07:17:33.775Z",
"uri": "https://api.viessmann.com/iot/v1/equipment/installations/2054585/gateways/7736172033094220/devices/0..."
},

It returns following error code

{"viErrorId":"req-617f466298234d05bc1803987a964355","statusCode":422,"errorType":"VALIDATION_ERROR","message":"VALIDATION_ERROR","validationErrors":[{"path":["commandBody"],"type":"any.invalid","message":"invalid value, most likely wrong format"}],"extendedPayload":{"commandBody":"EMPTY_MODEL"}}

but the API Call does not specify any command body ...