diff --git a/src/Client.php b/src/Client.php
index 640bad5..443ade6 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -187,7 +187,7 @@ private function reConnect(int $delay)
 
     public function send(array $data, bool $response = true)
     {
-        if ($this->config['protocol_level'] === 5) {
+        if ($this->config['protocol_level'] === ProtocolInterface::MQTT_PROTOCOL_LEVEL_5_0) {
             $package = ProtocolV5::pack($data);
         } else {
             $package = Protocol::pack($data);
@@ -218,7 +218,7 @@ public function recv()
                 throw new RuntimeException($errMsg, $this->client->errCode);
             }
         } elseif (is_string($response) && strlen($response) > 0) {
-            if ($this->config['protocol_level'] === 5) {
+            if ($this->config['protocol_level'] === ProtocolInterface::MQTT_PROTOCOL_LEVEL_5_0) {
                 return ProtocolV5::unpack($response);
             }
 
diff --git a/tests/V3/PacketTest.php b/tests/V3/PacketTest.php
index 05840f6..c38830c 100644
--- a/tests/V3/PacketTest.php
+++ b/tests/V3/PacketTest.php
@@ -123,10 +123,10 @@ public function testClose(Client $client)
 
     public function testPublishNonTopic()
     {
-        $client = new Client(getTestMQTT5ConnectConfig(false), SWOOLE_MQTT_CONFIG);
+        $client = new Client(getTestConnectConfig(false), SWOOLE_MQTT_CONFIG);
         $client->connect();
         $this->expectException(ProtocolException::class);
-        $this->expectExceptionMessage('Protocol Error, Topic cannot be empty or need to set topic_alias');
+        $this->expectExceptionMessage('Protocol Error, Topic cannot be empty');
         $client->publish('', 'hello,simps');
 
         return $client;