diff --git a/miniconf.py b/miniconf.py
index 7f88f65..644e026 100644
--- a/miniconf.py
+++ b/miniconf.py
@@ -16,6 +16,7 @@ from gmqtt import Client as MqttClient
 
 LOGGER = logging.getLogger(__name__)
 
+
 class Miniconf:
     """An asynchronous API for controlling Miniconf devices using MQTT."""
 
@@ -33,64 +34,64 @@ class Miniconf:
             client: A connected MQTT5 client.
             prefix: The MQTT toptic prefix of the device to control.
         """
-        self.uuid = uuid.uuid1()
         self.request_id = 0
         self.client = client
         self.prefix = prefix
         self.inflight = {}
         self.client.on_message = self._handle_response
-        self.client.subscribe(f'{prefix}/response/{self.uuid.hex}')
+        self.response_topic = f'{prefix}/response/{uuid.uuid1().hex}'
+        self.client.subscribe(self.response_topic)
 
-    def _handle_response(self, _client, _topic, payload, _qos, properties):
+    def _handle_response(self, _client, topic, payload, _qos, properties):
         """Callback function for when messages are received over MQTT.
 
         Args:
             _client: The MQTT client.
-            _topic: The topic that the message was received on.
+            topic: The topic that the message was received on.
             payload: The payload of the message.
             _qos: The quality-of-service level of the received packet
             properties: A dictionary of properties associated with the message.
         """
-        # Extract corrleation data from the properties
-        correlation_data = json.loads(properties['correlation_data'][0].decode('ascii'))
+        if topic == self.response_topic:
+            # Extract request_id corrleation data from the properties
+            request_id = int.from_bytes(
+                properties['correlation_data'][0], 'big')
 
-        # Get the request ID from the correlation data
-        request_id = correlation_data['request_id']
+            self.inflight[request_id].set_result(json.loads(payload))
+            del self.inflight[request_id]
+        else:
+            LOGGER.warn('Unexpected message on "%s"', topic)
 
-        self.inflight[request_id].set_result(json.loads(payload))
-        del self.inflight[request_id]
-
-
-    async def command(self, path, value):
+    async def command(self, path, value, retain=True):
         """Write the provided data to the specified path.
 
         Args:
             path: The path to write the message to.
             value: The value to write to the path.
+            retain: Retain the MQTT message changing the setting
+                by the broker.
 
         Returns:
             The response to the command as a dictionary.
         """
-        setting_topic = f'{self.prefix}/settings/{path}'
-        response_topic = f'{self.prefix}/response/{self.uuid.hex}'
+        topic = f'{self.prefix}/settings/{path}'
 
-        # Assign a unique identifier to this update request.
-        request_id = self.request_id
-        self.request_id += 1
-        assert request_id not in self.inflight, 'Invalid ID encountered'
-
-        correlation_data = json.dumps({
-            'request_id': request_id,
-        }).encode('ascii')
-
-        value = json.dumps(value)
-        LOGGER.info('Sending %s to "%s"', value, setting_topic)
         fut = asyncio.get_running_loop().create_future()
 
-        self.inflight[request_id] = fut
-        self.client.publish(setting_topic, payload=value, qos=0, retain=True,
-                            response_topic=response_topic,
-                            correlation_data=correlation_data)
+        # Assign unique correlation data for response dispatch
+        assert self.request_id not in self.inflight
+        self.inflight[self.request_id] = fut
+        correlation_data = self.request_id.to_bytes(4, 'big')
+        self.request_id += 1
+
+        payload = json.dumps(value)
+        LOGGER.info('Sending "%s" to "%s"', value, topic)
+
+        self.client.publish(
+            topic, payload=payload, qos=0, retain=retain,
+            response_topic=self.response_topic,
+            correlation_data=correlation_data)
+
         return await fut
 
 
@@ -100,16 +101,20 @@ def main():
         description='Miniconf command line interface.',
         formatter_class=argparse.RawDescriptionHelpFormatter,
         epilog='''Examples:
-%(prog)s dt/sinara/stabilizer afe/0='"G2"' iir_ch/0/0=\
-'{"y_min": -32767, "y_max": 32767, "y_offset": 0, "ba": [1.0, 0, 0, 0, 0]}'
+%(prog)s dt/sinara/dual-iir/00-11-22-33-aa-bb iir_ch/0/0=\
+'{"y_min":-32767,"y_max":32767,"y_offset":0,"ba":[1.0,0,0,0,0]}'
+%(prog)s dt/sinara/lockin/00-11-22-33-aa-bb afe/0='"G2"'\
 ''')
     parser.add_argument('-v', '--verbose', action='count', default=0,
                         help='Increase logging verbosity')
     parser.add_argument('--broker', '-b', default='mqtt', type=str,
                         help='The MQTT broker address')
+    parser.add_argument('--no-retain', '-n', default=False,
+                        action='store_true',
+                        help='Do not retain the affected settings')
     parser.add_argument('prefix', type=str,
                         help='The MQTT topic prefix of the target')
-    parser.add_argument('settings', metavar="KEY=VALUE", nargs='+',
+    parser.add_argument('settings', metavar="PATH=VALUE", nargs='+',
                         help='JSON encoded values for settings path keys.')
 
     args = parser.parse_args()
@@ -122,9 +127,10 @@ def main():
 
     async def configure_settings():
         interface = await Miniconf.create(args.prefix, args.broker)
-        for key_value in args.settings:
-            path, value = key_value.split("=", 1)
-            response = await interface.command(path, json.loads(value))
+        for setting in args.settings:
+            path, value = setting.split("=", 1)
+            response = await interface.command(path, json.loads(value),
+                                               not args.no_retain)
             print(f'{path}: {response}')
             if response['code'] != 0:
                 return response['code']