{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "Update Contract History (request)",
  "description": "Request for contract update history.",
  "type": "object",
  "auth_required": 1,
  "auth_scopes": ["trade"],
  "additionalProperties": false,
  "required": ["contract_update_history", "contract_id"],
  "properties": {
    "contract_update_history": {
      "description": "Must be `1`",
      "type": "integer",
      "enum": [1]
    },
    "contract_id": {
      "description": "Internal unique contract identifier.",
      "type": "integer"
    },
    "limit": {
      "description": "[Optional] Maximum number of historical updates to receive.",
      "type": "number",
      "default": 500,
      "maximum": 999,
      "minimum": 1
    },
    "passthrough": {
      "description": "[Optional] Used to pass data through the websocket, which may be retrieved via the `echo_req` output field.",
      "type": "object"
    },
    "req_id": {
      "description": "[Optional] Used to map request to response.",
      "type": "integer"
    }
  }
}