diff --git a/src/ebusd/mqtthandler.h b/src/ebusd/mqtthandler.h
index 87c56e19..eccf23d8 100644
--- a/src/ebusd/mqtthandler.h
+++ b/src/ebusd/mqtthandler.h
@@ -98,6 +98,7 @@ class MqttHandler : public DataSink, public DataSource, public Thread {
    * Build the MQTT topic string for the @a Message.
    * @param message the @a Message to build the topic string for.
    * @param fieldIndex the optional field index for the field column, or -1.
+   * @param suffix the optional suffix string to append.
    * @return the topic string.
    */
   string getTopic(const Message* message, ssize_t fieldIndex = -1, const string& suffix = "");