text: // Copyright Takatoshi Kondo 2019
  //
  // Distributed under the Boost Software License, Version 1.0.
  // (See accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt)
  
  #if !defined(MQTT_PROTOCOL_VERSION_HPP)
  #define MQTT_PROTOCOL_VERSION_HPP
  
  #include <cstdint>
  #include <mqtt/namespace.hpp>
  
  namespace MQTT_NS {
  
  enum class protocol_version {
      undetermined  = 0,
      v3_1_1        = 4,
      v5            = 5,
  };
  
  } // namespace MQTT_NS
  
  #endif // MQTT_PROTOCOL_VERSION_HPP
  