diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md
index 407ee95e994..d4f0f1b5fec 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeApi.md
@@ -450,7 +450,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **testJsonFormData**
-> testJsonFormData($param, $param2)
+> testJsonFormData($body_4)
 
 test json serialization of form data
 
@@ -464,11 +464,10 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$param = "param_example"; // string | field1
-$param2 = "param2_example"; // string | field2
+$body_4 = new \Swagger\Client\Model\Body4(); // \Swagger\Client\Model\Body4 | 
 
 try {
-    $apiInstance->testJsonFormData($param, $param2);
+    $apiInstance->testJsonFormData($body_4);
 } catch (Exception $e) {
     echo 'Exception when calling FakeApi->testJsonFormData: ', $e->getMessage(), PHP_EOL;
 }
@@ -479,8 +478,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **param** | **string**| field1 |
- **param2** | **string**| field2 |
+ **body_4** | [**\Swagger\Client\Model\Body4**](../Model/Body4.md)|  | [optional]
 
 ### Return type
 
@@ -492,7 +490,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: application/x-www-form-urlencoded
+ - **Content-Type**: application/json
  - **Accept**: Not defined
 
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php
index 306cf69eefb..974a1632f3a 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeApi.php
@@ -2239,16 +2239,15 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  string $param field1 (required)
-     * @param  string $param2 field2 (required)
+     * @param  \Swagger\Client\Model\Body4 $body_4 body_4 (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function testJsonFormData($param, $param2)
+    public function testJsonFormData($body_4 = null)
     {
-        $this->testJsonFormDataWithHttpInfo($param, $param2);
+        $this->testJsonFormDataWithHttpInfo($body_4);
     }
 
     /**
@@ -2256,17 +2255,16 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  string $param field1 (required)
-     * @param  string $param2 field2 (required)
+     * @param  \Swagger\Client\Model\Body4 $body_4 (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function testJsonFormDataWithHttpInfo($param, $param2)
+    public function testJsonFormDataWithHttpInfo($body_4 = null)
     {
         $returnType = '';
-        $request = $this->testJsonFormDataRequest($param, $param2);
+        $request = $this->testJsonFormDataRequest($body_4);
 
         try {
             $options = $this->createHttpClientOption();
@@ -2310,15 +2308,14 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  string $param field1 (required)
-     * @param  string $param2 field2 (required)
+     * @param  \Swagger\Client\Model\Body4 $body_4 (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testJsonFormDataAsync($param, $param2)
+    public function testJsonFormDataAsync($body_4 = null)
     {
-        return $this->testJsonFormDataAsyncWithHttpInfo($param, $param2)
+        return $this->testJsonFormDataAsyncWithHttpInfo($body_4)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -2331,16 +2328,15 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  string $param field1 (required)
-     * @param  string $param2 field2 (required)
+     * @param  \Swagger\Client\Model\Body4 $body_4 (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testJsonFormDataAsyncWithHttpInfo($param, $param2)
+    public function testJsonFormDataAsyncWithHttpInfo($body_4 = null)
     {
         $returnType = '';
-        $request = $this->testJsonFormDataRequest($param, $param2);
+        $request = $this->testJsonFormDataRequest($body_4);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -2368,26 +2364,13 @@ class FakeApi
     /**
      * Create request for operation 'testJsonFormData'
      *
-     * @param  string $param field1 (required)
-     * @param  string $param2 field2 (required)
+     * @param  \Swagger\Client\Model\Body4 $body_4 (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function testJsonFormDataRequest($param, $param2)
+    protected function testJsonFormDataRequest($body_4 = null)
     {
-        // verify the required parameter 'param' is set
-        if ($param === null || (is_array($param) && count($param) === 0)) {
-            throw new \InvalidArgumentException(
-                'Missing the required parameter $param when calling testJsonFormData'
-            );
-        }
-        // verify the required parameter 'param2' is set
-        if ($param2 === null || (is_array($param2) && count($param2) === 0)) {
-            throw new \InvalidArgumentException(
-                'Missing the required parameter $param2 when calling testJsonFormData'
-            );
-        }
 
         $resourcePath = '/fake/jsonFormData';
         $formParams = [];
@@ -2398,16 +2381,11 @@ class FakeApi
 
 
 
-        // form params
-        if ($param !== null) {
-            $formParams['param'] = ObjectSerializer::toFormValue($param);
-        }
-        // form params
-        if ($param2 !== null) {
-            $formParams['param2'] = ObjectSerializer::toFormValue($param2);
-        }
         // body params
         $_tempBody = null;
+        if (isset($body_4)) {
+            $_tempBody = $body_4;
+        }
 
         if ($multipart) {
             $headers = $this->headerSelector->selectHeadersForMultipart(
@@ -2416,7 +2394,7 @@ class FakeApi
         } else {
             $headers = $this->headerSelector->selectHeaders(
                 [],
-                ['application/x-www-form-urlencoded']
+                ['application/json']
             );
         }