{
   "id":"clientID9",
   "event":"subscribe",
   "success":true,
   "ts":1682242805633
}

{
   "topic":"maintenance_status",
   "ts":1682242806000,
   "data":[
      {
         "status": 2, // 0 is functioning, 2 is under maintenance
         "msg": "system is under maintenance",
         "scheduled_maintenance": {
            "startTime": 1618822380000,
            "endTime": 1618822440000
         }
      }
   ]
}