Protocol name will never be changed from MQTT.

lib/mqtt_protocol.h

@@ -22,10 +22,9 @@ Contributors:
 #define PROTOCOL_NAME_v31 "MQIsdp"
 #define PROTOCOL_VERSION_v31 3
 
-#define PROTOCOL_NAME_v311 "MQTT"
-#define PROTOCOL_VERSION_v311 4
+#define PROTOCOL_NAME "MQTT"
 
-#define PROTOCOL_NAME_v5 "MQTT"
+#define PROTOCOL_VERSION_v311 4
 #define PROTOCOL_VERSION_v5 5
 
 

lib/send_connect.c

@@ -99,7 +99,7 @@ int send__connect(struct mosquitto *mosq, uint16_t keepalive, bool clean_session
 	if(version == MQTT_PROTOCOL_V31){
 		packet__write_string(packet, PROTOCOL_NAME_v31, strlen(PROTOCOL_NAME_v31));
 	}else if(version == MQTT_PROTOCOL_V311){
-		packet__write_string(packet, PROTOCOL_NAME_v311, strlen(PROTOCOL_NAME_v311));
+		packet__write_string(packet, PROTOCOL_NAME, strlen(PROTOCOL_NAME));
 	}
 #if defined(WITH_BROKER) && defined(WITH_BRIDGE)
 	if(mosq->bridge && mosq->bridge->try_private && mosq->bridge->try_private_accepted){

src/handle_connect.c

@@ -182,7 +182,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 			goto handle_connect_error;
 		}
 		context->protocol = mosq_p_mqtt31;
-	}else if(!strcmp(protocol_name, PROTOCOL_NAME_v311)){
+	}else if(!strcmp(protocol_name, PROTOCOL_NAME)){
 		if((protocol_version&0x7F) != PROTOCOL_VERSION_v311){
 			if(db->config->connection_messages == true){
 				log__printf(NULL, MOSQ_LOG_INFO, "Invalid protocol version %d in CONNECT from %s.",