Bridge defaults to mqtt3.1.1 as per documentation.

src/conf.c

@@ -970,7 +970,7 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, const
 						cur_bridge->threshold = 10;
 						cur_bridge->try_private = true;
 						cur_bridge->attempt_unsubscribe = true;
-						cur_bridge->protocol_version = mosq_p_mqtt31;
+						cur_bridge->protocol_version = mosq_p_mqtt311;
 					}else{
 						log__printf(NULL, MOSQ_LOG_ERR, "Error: Empty connection value in configuration.");
 						return MOSQ_ERR_INVAL;

test/broker/06-bridge-b2br-disconnect-qos1.py

@@ -15,7 +15,7 @@ import mosq_test
 rc = 1
 keepalive = 60
 client_id = socket.gethostname()+".bridge_sample"
-connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+3)
+connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+4)
 connack_packet = mosq_test.gen_connack(rc=0)
 
 mid = 1

test/broker/06-bridge-b2br-disconnect-qos2.py

@@ -15,7 +15,7 @@ import mosq_test
 rc = 1
 keepalive = 60
 client_id = socket.gethostname()+".bridge_sample"
-connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+3)
+connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+4)
 connack_packet = mosq_test.gen_connack(rc=0)
 
 mid = 1

test/broker/06-bridge-br2b-disconnect-qos1.py

@@ -16,7 +16,7 @@ import mosq_test
 rc = 1
 keepalive = 60
 client_id = socket.gethostname()+".bridge_sample"
-connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+3)
+connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+4)
 connack_packet = mosq_test.gen_connack(rc=0)
 
 mid = 1

test/broker/06-bridge-br2b-disconnect-qos2.py

@@ -16,7 +16,7 @@ import mosq_test
 rc = 1
 keepalive = 60
 client_id = socket.gethostname()+".bridge_sample"
-connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+3)
+connect_packet = mosq_test.gen_connect(client_id, keepalive=keepalive, clean_session=False, proto_ver=128+4)
 connack_packet = mosq_test.gen_connack(rc=0)
 
 mid = 1

test/broker/06-bridge-fail-persist-resend-qos1.py

@@ -16,7 +16,7 @@ import mosq_test
 
 rc = 1
 keepalive = 60
-connect_packet = mosq_test.gen_connect("bridge-u-test", keepalive=keepalive, proto_ver=3)
+connect_packet = mosq_test.gen_connect("bridge-u-test", keepalive=keepalive)
 connack_packet = mosq_test.gen_connack(rc=0)
 
 mid = 180

test/broker/06-bridge-fail-persist-resend-qos2.py

@@ -16,7 +16,7 @@ import mosq_test
 
 rc = 1
 keepalive = 60
-connect_packet = mosq_test.gen_connect("bridge-u-test", keepalive=keepalive, proto_ver=3)
+connect_packet = mosq_test.gen_connect("bridge-u-test", keepalive=keepalive)
 connack_packet = mosq_test.gen_connack(rc=0)
 
 mid = 180