diff --git a/client/client_shared.c b/client/client_shared.c
index 13972770..88112201 100644
--- a/client/client_shared.c
+++ b/client/client_shared.c
@@ -1011,7 +1011,7 @@ int client_id_generate(struct mosq_config *cfg, const char *id_base)
 			return 1;
 		}
 		snprintf(cfg->id, strlen(cfg->id_prefix)+10, "%s%d", cfg->id_prefix, getpid());
-	}else if(!cfg->id){
+	}else if(!cfg->id && (cfg->protocol_version == MQTT_PROTOCOL_V31 || cfg->protocol_version == MQTT_PROTOCOL_V311)){
 		hostname[0] = '\0';
 		gethostname(hostname, 256);
 		hostname[255] = '\0';
diff --git a/client/pub_client.c b/client/pub_client.c
index 139bb3aa..bede0032 100644
--- a/client/pub_client.c
+++ b/client/pub_client.c
@@ -48,7 +48,7 @@ int my_publish(struct mosquitto *mosq, int *mid, const char *topic, int payloadl
 }
 
 
-void my_connect_callback(struct mosquitto *mosq, void *obj, int result)
+void my_connect_callback(struct mosquitto *mosq, void *obj, int result, int flags, const mosquitto_property *properties)
 {
 	int rc = MOSQ_ERR_SUCCESS;
 
@@ -262,7 +262,7 @@ int main(int argc, char *argv[])
 	if(cfg.debug){
 		mosquitto_log_callback_set(mosq, my_log_callback);
 	}
-	mosquitto_connect_callback_set(mosq, my_connect_callback);
+	mosquitto_connect_v5_callback_set(mosq, my_connect_callback);
 	mosquitto_disconnect_v5_callback_set(mosq, my_disconnect_callback);
 	mosquitto_publish_callback_set(mosq, my_publish_callback);
 
diff --git a/client/pub_shared.h b/client/pub_shared.h
index feaa22eb..22f88e62 100644
--- a/client/pub_shared.h
+++ b/client/pub_shared.h
@@ -26,7 +26,7 @@ extern int status;
 extern struct mosq_config cfg;
 
 
-void my_connect_callback(struct mosquitto *mosq, void *obj, int result);
+void my_connect_callback(struct mosquitto *mosq, void *obj, int result, int flags, const mosquitto_property *properties);
 void my_disconnect_callback(struct mosquitto *mosq, void *obj, int rc, const mosquitto_property *properties);
 void my_publish_callback(struct mosquitto *mosq, void *obj, int mid);
 void my_log_callback(struct mosquitto *mosq, void *obj, int level, const char *str);
diff --git a/client/sub_client.c b/client/sub_client.c
index cd297b0b..1a26bcb0 100644
--- a/client/sub_client.c
+++ b/client/sub_client.c
@@ -85,7 +85,7 @@ void my_message_callback(struct mosquitto *mosq, void *obj, const struct mosquit
 	}
 }
 
-void my_connect_callback(struct mosquitto *mosq, void *obj, int result, int flags)
+void my_connect_callback(struct mosquitto *mosq, void *obj, int result, int flags, const mosquitto_property *properties)
 {
 	int i;
 
@@ -281,7 +281,7 @@ int main(int argc, char *argv[])
 		mosquitto_log_callback_set(mosq, my_log_callback);
 		mosquitto_subscribe_callback_set(mosq, my_subscribe_callback);
 	}
-	mosquitto_connect_with_flags_callback_set(mosq, my_connect_callback);
+	mosquitto_connect_v5_callback_set(mosq, my_connect_callback);
 	mosquitto_message_callback_set(mosq, my_message_callback);
 
 	rc = client_connect(mosq, &cfg);