diff --git a/plugins/mqtt/aws-iot.json b/plugins/mqtt/aws-iot.json
index 8ad79c18..237e8065 100644
--- a/plugins/mqtt/aws-iot.json
+++ b/plugins/mqtt/aws-iot.json
@@ -1,23 +1,4 @@
 {
-  "version": {
-    "name": "MQTT Version",
-    "name_zh": "MQTT 版本",
-    "type": "map",
-    "attribute": "optional",
-    "default": 5,
-    "valid": {
-      "map": [
-        {
-          "key": "3.1.1",
-          "value": 4
-        },
-        {
-          "key": "5.0",
-          "value": 5
-        }
-      ]
-    }
-  },
   "client-id": {
     "name": "Client ID",
     "name_zh": "客户端 ID",
diff --git a/plugins/mqtt/azure-iot.json b/plugins/mqtt/azure-iot.json
index aca21359..14fd6ecd 100644
--- a/plugins/mqtt/azure-iot.json
+++ b/plugins/mqtt/azure-iot.json
@@ -1,23 +1,4 @@
 {
-  "version": {
-    "name": "MQTT Version",
-    "name_zh": "MQTT 版本",
-    "type": "map",
-    "attribute": "optional",
-    "default": 5,
-    "valid": {
-      "map": [
-        {
-          "key": "3.1.1",
-          "value": 4
-        },
-        {
-          "key": "5.0",
-          "value": 5
-        }
-      ]
-    }
-  },
   "device-id": {
     "name": "Device ID",
     "name_zh": "设备 ID",
diff --git a/plugins/mqtt/azure_iot_plugin.c b/plugins/mqtt/azure_iot_plugin.c
index 3aa17b66..7c997997 100644
--- a/plugins/mqtt/azure_iot_plugin.c
+++ b/plugins/mqtt/azure_iot_plugin.c
@@ -73,12 +73,6 @@ static int azure_parse_config(neu_plugin_t *plugin, const char *setting,
     char *      write_resp_topic = NULL;
     char *      username         = NULL;
 
-    neu_json_elem_t version = {
-        .name      = "version",
-        .t         = NEU_JSON_INT,
-        .v.val_int = NEU_MQTT_VERSION_V5,         // default to V5
-        .attribute = NEU_JSON_ATTRIBUTE_OPTIONAL, // for backward compatibility
-    };
     neu_json_elem_t client_id = { .name = "device-id", .t = NEU_JSON_STR };
     neu_json_elem_t qos       = { .name = "qos", .t = NEU_JSON_INT };
     neu_json_elem_t format    = { .name = "format", .t = NEU_JSON_INT };
@@ -101,14 +95,6 @@ static int azure_parse_config(neu_plugin_t *plugin, const char *setting,
         goto error;
     }
 
-    ret = neu_parse_param(setting, &err_param, 1, &version);
-    if (0 != ret) {
-        plog_error(
-            plugin,
-            "parsing mqtt version fail, key: `%s`. Set default version: mqttv5",
-            err_param);
-    }
-
     // client-id, required
     if (0 == strlen(client_id.v.val_str)) {
         plog_error(plugin, "setting empty client-id");
@@ -179,7 +165,7 @@ static int azure_parse_config(neu_plugin_t *plugin, const char *setting,
         goto error;
     }
 
-    config->version             = version.v.val_int;
+    config->version             = NEU_MQTT_VERSION_V311;
     config->client_id           = client_id.v.val_str;
     config->qos                 = qos.v.val_int;
     config->format              = format.v.val_int;
diff --git a/plugins/mqtt/mqtt.json b/plugins/mqtt/mqtt.json
index 7862d523..05abf4f5 100644
--- a/plugins/mqtt/mqtt.json
+++ b/plugins/mqtt/mqtt.json
@@ -4,7 +4,7 @@
     "name_zh": "MQTT 版本",
     "type": "map",
     "attribute": "optional",
-    "default": 5,
+    "default": 4,
     "valid": {
       "map": [
         {
diff --git a/plugins/mqtt/mqtt_config.c b/plugins/mqtt/mqtt_config.c
index 6a9ced31..834ec2aa 100644
--- a/plugins/mqtt/mqtt_config.c
+++ b/plugins/mqtt/mqtt_config.c
@@ -221,7 +221,7 @@ int mqtt_config_parse(neu_plugin_t *plugin, const char *setting,
     neu_json_elem_t version = {
         .name      = "version",
         .t         = NEU_JSON_INT,
-        .v.val_int = NEU_MQTT_VERSION_V5,         // default to V5
+        .v.val_int = NEU_MQTT_VERSION_V311,       // default to V311
         .attribute = NEU_JSON_ATTRIBUTE_OPTIONAL, // for backward compatibility
     };
     neu_json_elem_t client_id = { .name = "client-id", .t = NEU_JSON_STR };
@@ -276,10 +276,8 @@ int mqtt_config_parse(neu_plugin_t *plugin, const char *setting,
 
     ret = neu_parse_param(setting, &err_param, 1, &version);
     if (0 != ret) {
-        plog_error(
-            plugin,
-            "parsing mqtt version fail, key: `%s`. Set default version: mqttv5",
-            err_param);
+        plog_error(plugin, "parsing mqtt version fail, key: `%s`.", err_param);
+        goto error;
     }
 
     // client-id, required