/// <summary>
        /// Handler for APP_DEPENDENCY
        /// </summary>
        /// <param name="message">The message received</param>
        protected void AppDependency(dynamic message)
        {
            var dep = message["audioOutput"];
            foreach (var kv in dep)
            {
                string instance = kv.Key;
                string state = kv.Value;

                if (!speakers.ContainsKey(instance))
                {
                    MycroftSpeaker speaker = new MycroftSpeaker(instance, state, port);
                    speakers[instance] = speaker;
                    port++;
                }
                speakers[instance].Status = state;
            }
        }