diff --git a/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
index ac2cd975ddf..c4b70f133e2 100644
--- a/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -853,7 +853,7 @@ paths:
           description: successful operation
       requestBody:
         content:
-          application/json:
+          application/x-www-form-urlencoded:
             schema:
               type: object
               properties:
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/README.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/README.md
index 953b70f1c8d..3ff73615c69 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/README.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/README.md
@@ -61,7 +61,7 @@ $apiInstance = new Swagger\Client\Api\AnotherFakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$client = new \Swagger\Client\Model\Client(); // Client | client model
+$client = new \Swagger\Client\Model\Client(); // \Swagger\Client\Model\Client | client model
 
 try {
     $result = $apiInstance->testSpecialTags($client);
@@ -121,7 +121,6 @@ Class | Method | HTTP request | Description
  - [ArrayOfArrayOfNumberOnly](docs/Model/ArrayOfArrayOfNumberOnly.md)
  - [ArrayOfNumberOnly](docs/Model/ArrayOfNumberOnly.md)
  - [ArrayTest](docs/Model/ArrayTest.md)
- - [Body4](docs/Model/Body4.md)
  - [Capitalization](docs/Model/Capitalization.md)
  - [Cat](docs/Model/Cat.md)
  - [Category](docs/Model/Category.md)
@@ -148,7 +147,7 @@ Class | Method | HTTP request | Description
  - [OuterString](docs/Model/OuterString.md)
  - [Pet](docs/Model/Pet.md)
  - [ReadOnlyFirst](docs/Model/ReadOnlyFirst.md)
- - [SpecialModelName_](docs/Model/SpecialModelName_.md)
+ - [SpecialModelName](docs/Model/SpecialModelName.md)
  - [Tag](docs/Model/Tag.md)
  - [User](docs/Model/User.md)
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/AnotherFakeApi.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/AnotherFakeApi.md
index 668341b0e2c..4e5c5ecaf58 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/AnotherFakeApi.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/AnotherFakeApi.md
@@ -24,7 +24,7 @@ $apiInstance = new Swagger\Client\Api\AnotherFakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$client = new \Swagger\Client\Model\Client(); // Client | client model
+$client = new \Swagger\Client\Model\Client(); // \Swagger\Client\Model\Client | client model
 
 try {
     $result = $apiInstance->testSpecialTags($client);
@@ -39,7 +39,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **client** | [**Client**](../Model/Client.md)| client model |
+ **client** | [**\Swagger\Client\Model\Client**](../Model/Client.md)| client model |
 
 ### Return type
 
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 d7ae0b50611..6282932aadf 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
@@ -81,7 +81,7 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$outer_composite = new \Swagger\Client\Model\OuterComposite(); // OuterComposite | Input composite as post body
+$outer_composite = new \Swagger\Client\Model\OuterComposite(); // \Swagger\Client\Model\OuterComposite | Input composite as post body
 
 try {
     $result = $apiInstance->fakeOuterCompositeSerialize($outer_composite);
@@ -96,7 +96,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **outer_composite** | [**OuterComposite**](../Model/OuterComposite.md)| Input composite as post body | [optional]
+ **outer_composite** | [**\Swagger\Client\Model\OuterComposite**](../Model/OuterComposite.md)| Input composite as post body | [optional]
 
 ### Return type
 
@@ -228,7 +228,7 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$client = new \Swagger\Client\Model\Client(); // Client | client model
+$client = new \Swagger\Client\Model\Client(); // \Swagger\Client\Model\Client | client model
 
 try {
     $result = $apiInstance->testClientModel($client);
@@ -243,7 +243,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **client** | [**Client**](../Model/Client.md)| client model |
+ **client** | [**\Swagger\Client\Model\Client**](../Model/Client.md)| client model |
 
 ### Return type
 
@@ -359,11 +359,11 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     new GuzzleHttp\Client()
 );
 $enum_header_string_array = array("enum_header_string_array_example"); // string[] | Header parameter enum test (string array)
-$enum_header_string = "enum_header_string_example"; // string | Header parameter enum test (string)
+$enum_header_string = "-efg"; // string | Header parameter enum test (string)
 $enum_query_string_array = array("enum_query_string_array_example"); // string[] | Query parameter enum test (string array)
-$enum_query_string = "enum_query_string_example"; // string | Query parameter enum test (string)
+$enum_query_string = "-efg"; // string | Query parameter enum test (string)
 $enum_query_integer = 56; // int | Query parameter enum test (double)
-$enum_query_double = 1.2; // double | Query parameter enum test (double)
+$enum_query_double = 3.4; // double | Query parameter enum test (double)
 $enum_form_string_array = new \Swagger\Client\Model\array(); // string[] | Form parameter enum test (string array)
 $enum_form_string = "enum_form_string_example"; // string | Form parameter enum test (string)
 
@@ -380,9 +380,9 @@ try {
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
  **enum_header_string_array** | [**string[]**](../Model/string.md)| Header parameter enum test (string array) | [optional]
- **enum_header_string** | **string**| Header parameter enum test (string) | [optional]
+ **enum_header_string** | **string**| Header parameter enum test (string) | [optional] [default to -efg]
  **enum_query_string_array** | [**string[]**](../Model/string.md)| Query parameter enum test (string array) | [optional]
- **enum_query_string** | **string**| Query parameter enum test (string) | [optional]
+ **enum_query_string** | **string**| Query parameter enum test (string) | [optional] [default to -efg]
  **enum_query_integer** | **int**| Query parameter enum test (double) | [optional]
  **enum_query_double** | **double**| Query parameter enum test (double) | [optional]
  **enum_form_string_array** | [**string[]**](../Model/array.md)| Form parameter enum test (string array) | [optional]
@@ -404,7 +404,7 @@ 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)
 
 # **testInlineAdditionalProperties**
-> testInlineAdditionalProperties($unknown_base_type)
+> testInlineAdditionalProperties($UNKNOWN_PARAM_NAME)
 
 test inline additionalProperties
 
@@ -418,10 +418,10 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$unknown_base_type = new \Swagger\Client\Model\UNKNOWN_BASE_TYPE(); // map[string,string] | request body
+$UNKNOWN_PARAM_NAME = new \Swagger\Client\Model\null(); //  | request body
 
 try {
-    $apiInstance->testInlineAdditionalProperties($unknown_base_type);
+    $apiInstance->testInlineAdditionalProperties($UNKNOWN_PARAM_NAME);
 } catch (Exception $e) {
     echo 'Exception when calling FakeApi->testInlineAdditionalProperties: ', $e->getMessage(), PHP_EOL;
 }
@@ -432,7 +432,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **unknown_base_type** | [**map[string,string]**](../Model/UNKNOWN_BASE_TYPE.md)| request body |
+ **UNKNOWN_PARAM_NAME** | [****](../Model/.md)| request body |
 
 ### Return type
 
@@ -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($body4)
+> testJsonFormData($param, $param2)
 
 test json serialization of form data
 
@@ -464,10 +464,11 @@ $apiInstance = new Swagger\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$body4 = new \Swagger\Client\Model\Body4(); // Body4 | 
+$param = "param_example"; // string | field1
+$param2 = "param2_example"; // string | field2
 
 try {
-    $apiInstance->testJsonFormData($body4);
+    $apiInstance->testJsonFormData($param, $param2);
 } catch (Exception $e) {
     echo 'Exception when calling FakeApi->testJsonFormData: ', $e->getMessage(), PHP_EOL;
 }
@@ -478,7 +479,8 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body4** | [**Body4**](../Model/Body4.md)|  | [optional]
+ **param** | **string**| field1 |
+ **param2** | **string**| field2 |
 
 ### Return type
 
@@ -490,7 +492,7 @@ No authorization required
 
 ### HTTP request headers
 
- - **Content-Type**: application/json
+ - **Content-Type**: application/x-www-form-urlencoded
  - **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/docs/Api/FakeClassnameTags123Api.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeClassnameTags123Api.md
index 6314df1bc73..2042cf0d0f3 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeClassnameTags123Api.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/FakeClassnameTags123Api.md
@@ -30,7 +30,7 @@ $apiInstance = new Swagger\Client\Api\FakeClassnameTags123Api(
     new GuzzleHttp\Client(),
     $config
 );
-$client = new \Swagger\Client\Model\Client(); // Client | client model
+$client = new \Swagger\Client\Model\Client(); // \Swagger\Client\Model\Client | client model
 
 try {
     $result = $apiInstance->testClassname($client);
@@ -45,7 +45,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **client** | [**Client**](../Model/Client.md)| client model |
+ **client** | [**\Swagger\Client\Model\Client**](../Model/Client.md)| client model |
 
 ### Return type
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md
index 7f272230718..19329515e47 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/PetApi.md
@@ -33,7 +33,7 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     new GuzzleHttp\Client(),
     $config
 );
-$pet = new \Swagger\Client\Model\Pet(); // Pet | Pet object that needs to be added to the store
+$pet = new \Swagger\Client\Model\Pet(); // \Swagger\Client\Model\Pet | Pet object that needs to be added to the store
 
 try {
     $apiInstance->addPet($pet);
@@ -47,7 +47,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **pet** | [**Pet**](../Model/Pet.md)| Pet object that needs to be added to the store |
+ **pet** | [**\Swagger\Client\Model\Pet**](../Model/Pet.md)| Pet object that needs to be added to the store |
 
 ### Return type
 
@@ -83,7 +83,7 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     new GuzzleHttp\Client(),
     $config
 );
-$pet_id = 789; // int | Pet id to delete
+$pet_id = 56; // int | Pet id to delete
 $api_key = "api_key_example"; // string | 
 
 try {
@@ -245,7 +245,7 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     new GuzzleHttp\Client(),
     $config
 );
-$pet_id = 789; // int | ID of pet to return
+$pet_id = 56; // int | ID of pet to return
 
 try {
     $result = $apiInstance->getPetById($pet_id);
@@ -296,7 +296,7 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     new GuzzleHttp\Client(),
     $config
 );
-$pet = new \Swagger\Client\Model\Pet(); // Pet | Pet object that needs to be added to the store
+$pet = new \Swagger\Client\Model\Pet(); // \Swagger\Client\Model\Pet | Pet object that needs to be added to the store
 
 try {
     $apiInstance->updatePet($pet);
@@ -310,7 +310,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **pet** | [**Pet**](../Model/Pet.md)| Pet object that needs to be added to the store |
+ **pet** | [**\Swagger\Client\Model\Pet**](../Model/Pet.md)| Pet object that needs to be added to the store |
 
 ### Return type
 
@@ -346,7 +346,7 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     new GuzzleHttp\Client(),
     $config
 );
-$pet_id = 789; // int | ID of pet that needs to be updated
+$pet_id = 56; // int | ID of pet that needs to be updated
 $name = "name_example"; // string | Updated name of the pet
 $status = "status_example"; // string | Updated status of the pet
 
@@ -400,7 +400,7 @@ $apiInstance = new Swagger\Client\Api\PetApi(
     new GuzzleHttp\Client(),
     $config
 );
-$pet_id = 789; // int | ID of pet to update
+$pet_id = 56; // int | ID of pet to update
 $additional_metadata = "additional_metadata_example"; // string | Additional data to pass to server
 $file = "/path/to/file.txt"; // \SplFileObject | file to upload
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/StoreApi.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/StoreApi.md
index 1b1f88a006e..a36b5627608 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/StoreApi.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/StoreApi.md
@@ -126,7 +126,7 @@ $apiInstance = new Swagger\Client\Api\StoreApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$order_id = 789; // int | ID of pet that needs to be fetched
+$order_id = 56; // int | ID of pet that needs to be fetched
 
 try {
     $result = $apiInstance->getOrderById($order_id);
@@ -173,7 +173,7 @@ $apiInstance = new Swagger\Client\Api\StoreApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$order = new \Swagger\Client\Model\Order(); // Order | order placed for purchasing the pet
+$order = new \Swagger\Client\Model\Order(); // \Swagger\Client\Model\Order | order placed for purchasing the pet
 
 try {
     $result = $apiInstance->placeOrder($order);
@@ -188,7 +188,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **order** | [**Order**](../Model/Order.md)| order placed for purchasing the pet |
+ **order** | [**\Swagger\Client\Model\Order**](../Model/Order.md)| order placed for purchasing the pet |
 
 ### Return type
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/UserApi.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/UserApi.md
index a4f2313aba9..e51574b635d 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/UserApi.md
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Api/UserApi.md
@@ -31,7 +31,7 @@ $apiInstance = new Swagger\Client\Api\UserApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$user = new \Swagger\Client\Model\User(); // User | Created user object
+$user = new \Swagger\Client\Model\User(); // \Swagger\Client\Model\User | Created user object
 
 try {
     $apiInstance->createUser($user);
@@ -45,7 +45,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **user** | [**User**](../Model/User.md)| Created user object |
+ **user** | [**\Swagger\Client\Model\User**](../Model/User.md)| Created user object |
 
 ### Return type
 
@@ -77,7 +77,7 @@ $apiInstance = new Swagger\Client\Api\UserApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$user = array(new \Swagger\Client\Model\User()); // \Swagger\Client\Model\User[] | List of user object
+$user = array(new \Swagger\Client\Model\array()); // \Swagger\Client\Model\User[] | List of user object
 
 try {
     $apiInstance->createUsersWithArrayInput($user);
@@ -91,7 +91,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **user** | [**\Swagger\Client\Model\User[]**](../Model/User.md)| List of user object |
+ **user** | [**\Swagger\Client\Model\User[]**](../Model/array.md)| List of user object |
 
 ### Return type
 
@@ -123,7 +123,7 @@ $apiInstance = new Swagger\Client\Api\UserApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$user = array(new \Swagger\Client\Model\User()); // \Swagger\Client\Model\User[] | List of user object
+$user = array(new \Swagger\Client\Model\array()); // \Swagger\Client\Model\User[] | List of user object
 
 try {
     $apiInstance->createUsersWithListInput($user);
@@ -137,7 +137,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **user** | [**\Swagger\Client\Model\User[]**](../Model/User.md)| List of user object |
+ **user** | [**\Swagger\Client\Model\User[]**](../Model/array.md)| List of user object |
 
 ### Return type
 
@@ -358,7 +358,7 @@ $apiInstance = new Swagger\Client\Api\UserApi(
     new GuzzleHttp\Client()
 );
 $username = "username_example"; // string | name that need to be deleted
-$user = new \Swagger\Client\Model\User(); // User | Updated user object
+$user = new \Swagger\Client\Model\User(); // \Swagger\Client\Model\User | Updated user object
 
 try {
     $apiInstance->updateUser($username, $user);
@@ -373,7 +373,7 @@ try {
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
  **username** | **string**| name that need to be deleted |
- **user** | [**User**](../Model/User.md)| Updated user object |
+ **user** | [**\Swagger\Client\Model\User**](../Model/User.md)| Updated user object |
 
 ### Return type
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Model/SpecialModelName.md b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Model/SpecialModelName.md
new file mode 100644
index 00000000000..022ee19169c
--- /dev/null
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/docs/Model/SpecialModelName.md
@@ -0,0 +1,10 @@
+# SpecialModelName
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**special_property_name** | **int** |  | [optional] 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/AnotherFakeApi.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/AnotherFakeApi.php
index 274c96ea002..84d21b403f9 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/AnotherFakeApi.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/AnotherFakeApi.php
@@ -92,7 +92,7 @@ class AnotherFakeApi
      *
      * To test special tags
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -109,7 +109,7 @@ class AnotherFakeApi
      *
      * To test special tags
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -184,7 +184,7 @@ class AnotherFakeApi
      *
      * To test special tags
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -204,7 +204,7 @@ class AnotherFakeApi
      *
      * To test special tags
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -254,7 +254,7 @@ class AnotherFakeApi
     /**
      * Create request for operation 'testSpecialTags'
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
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 8d0f582727c..b3a1325a897 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
@@ -337,7 +337,7 @@ class FakeApi
     /**
      * Operation fakeOuterCompositeSerialize
      *
-     * @param  OuterComposite $outer_composite Input composite as post body (optional)
+     * @param  \Swagger\Client\Model\OuterComposite $outer_composite Input composite as post body (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -352,7 +352,7 @@ class FakeApi
     /**
      * Operation fakeOuterCompositeSerializeWithHttpInfo
      *
-     * @param  OuterComposite $outer_composite Input composite as post body (optional)
+     * @param  \Swagger\Client\Model\OuterComposite $outer_composite Input composite as post body (optional)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -427,7 +427,7 @@ class FakeApi
      *
      * 
      *
-     * @param  OuterComposite $outer_composite Input composite as post body (optional)
+     * @param  \Swagger\Client\Model\OuterComposite $outer_composite Input composite as post body (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -447,7 +447,7 @@ class FakeApi
      *
      * 
      *
-     * @param  OuterComposite $outer_composite Input composite as post body (optional)
+     * @param  \Swagger\Client\Model\OuterComposite $outer_composite Input composite as post body (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -497,7 +497,7 @@ class FakeApi
     /**
      * Create request for operation 'fakeOuterCompositeSerialize'
      *
-     * @param  OuterComposite $outer_composite Input composite as post body (optional)
+     * @param  \Swagger\Client\Model\OuterComposite $outer_composite Input composite as post body (optional)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
@@ -1080,7 +1080,7 @@ class FakeApi
      *
      * To test \"client\" model
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -1097,7 +1097,7 @@ class FakeApi
      *
      * To test \"client\" model
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -1172,7 +1172,7 @@ class FakeApi
      *
      * To test \"client\" model
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -1192,7 +1192,7 @@ class FakeApi
      *
      * To test \"client\" model
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -1242,7 +1242,7 @@ class FakeApi
     /**
      * Create request for operation 'testClientModel'
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
@@ -1738,9 +1738,9 @@ class FakeApi
      * To test enum parameters
      *
      * @param  string[] $enum_header_string_array Header parameter enum test (string array) (optional)
-     * @param  string $enum_header_string Header parameter enum test (string) (optional)
+     * @param  string $enum_header_string Header parameter enum test (string) (optional, default to -efg)
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
-     * @param  string $enum_query_string Query parameter enum test (string) (optional)
+     * @param  string $enum_query_string Query parameter enum test (string) (optional, default to -efg)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
      * @param  double $enum_query_double Query parameter enum test (double) (optional)
      * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
@@ -1750,7 +1750,7 @@ class FakeApi
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function testEnumParameters($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
+    public function testEnumParameters($enum_header_string_array = null, $enum_header_string = '-efg', $enum_query_string_array = null, $enum_query_string = '-efg', $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
     {
         $this->testEnumParametersWithHttpInfo($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_query_double, $enum_form_string_array, $enum_form_string);
     }
@@ -1761,9 +1761,9 @@ class FakeApi
      * To test enum parameters
      *
      * @param  string[] $enum_header_string_array Header parameter enum test (string array) (optional)
-     * @param  string $enum_header_string Header parameter enum test (string) (optional)
+     * @param  string $enum_header_string Header parameter enum test (string) (optional, default to -efg)
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
-     * @param  string $enum_query_string Query parameter enum test (string) (optional)
+     * @param  string $enum_query_string Query parameter enum test (string) (optional, default to -efg)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
      * @param  double $enum_query_double Query parameter enum test (double) (optional)
      * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
@@ -1773,7 +1773,7 @@ class FakeApi
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function testEnumParametersWithHttpInfo($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
+    public function testEnumParametersWithHttpInfo($enum_header_string_array = null, $enum_header_string = '-efg', $enum_query_string_array = null, $enum_query_string = '-efg', $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
     {
         $returnType = '';
         $request = $this->testEnumParametersRequest($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_query_double, $enum_form_string_array, $enum_form_string);
@@ -1821,9 +1821,9 @@ class FakeApi
      * To test enum parameters
      *
      * @param  string[] $enum_header_string_array Header parameter enum test (string array) (optional)
-     * @param  string $enum_header_string Header parameter enum test (string) (optional)
+     * @param  string $enum_header_string Header parameter enum test (string) (optional, default to -efg)
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
-     * @param  string $enum_query_string Query parameter enum test (string) (optional)
+     * @param  string $enum_query_string Query parameter enum test (string) (optional, default to -efg)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
      * @param  double $enum_query_double Query parameter enum test (double) (optional)
      * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
@@ -1832,7 +1832,7 @@ class FakeApi
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testEnumParametersAsync($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
+    public function testEnumParametersAsync($enum_header_string_array = null, $enum_header_string = '-efg', $enum_query_string_array = null, $enum_query_string = '-efg', $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
     {
         return $this->testEnumParametersAsyncWithHttpInfo($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_query_double, $enum_form_string_array, $enum_form_string)
             ->then(
@@ -1848,9 +1848,9 @@ class FakeApi
      * To test enum parameters
      *
      * @param  string[] $enum_header_string_array Header parameter enum test (string array) (optional)
-     * @param  string $enum_header_string Header parameter enum test (string) (optional)
+     * @param  string $enum_header_string Header parameter enum test (string) (optional, default to -efg)
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
-     * @param  string $enum_query_string Query parameter enum test (string) (optional)
+     * @param  string $enum_query_string Query parameter enum test (string) (optional, default to -efg)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
      * @param  double $enum_query_double Query parameter enum test (double) (optional)
      * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
@@ -1859,7 +1859,7 @@ class FakeApi
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testEnumParametersAsyncWithHttpInfo($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
+    public function testEnumParametersAsyncWithHttpInfo($enum_header_string_array = null, $enum_header_string = '-efg', $enum_query_string_array = null, $enum_query_string = '-efg', $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
     {
         $returnType = '';
         $request = $this->testEnumParametersRequest($enum_header_string_array, $enum_header_string, $enum_query_string_array, $enum_query_string, $enum_query_integer, $enum_query_double, $enum_form_string_array, $enum_form_string);
@@ -1891,9 +1891,9 @@ class FakeApi
      * Create request for operation 'testEnumParameters'
      *
      * @param  string[] $enum_header_string_array Header parameter enum test (string array) (optional)
-     * @param  string $enum_header_string Header parameter enum test (string) (optional)
+     * @param  string $enum_header_string Header parameter enum test (string) (optional, default to -efg)
      * @param  string[] $enum_query_string_array Query parameter enum test (string array) (optional)
-     * @param  string $enum_query_string Query parameter enum test (string) (optional)
+     * @param  string $enum_query_string Query parameter enum test (string) (optional, default to -efg)
      * @param  int $enum_query_integer Query parameter enum test (double) (optional)
      * @param  double $enum_query_double Query parameter enum test (double) (optional)
      * @param  string[] $enum_form_string_array Form parameter enum test (string array) (optional)
@@ -1902,7 +1902,7 @@ class FakeApi
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function testEnumParametersRequest($enum_header_string_array = null, $enum_header_string = null, $enum_query_string_array = null, $enum_query_string = null, $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
+    protected function testEnumParametersRequest($enum_header_string_array = null, $enum_header_string = '-efg', $enum_query_string_array = null, $enum_query_string = '-efg', $enum_query_integer = null, $enum_query_double = null, $enum_form_string_array = null, $enum_form_string = null)
     {
 
         $resourcePath = '/fake';
@@ -2021,15 +2021,15 @@ class FakeApi
      *
      * test inline additionalProperties
      *
-     * @param  map[string,string] $unknown_base_type request body (required)
+     * @param   $UNKNOWN_PARAM_NAME request body (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function testInlineAdditionalProperties($unknown_base_type)
+    public function testInlineAdditionalProperties($UNKNOWN_PARAM_NAME)
     {
-        $this->testInlineAdditionalPropertiesWithHttpInfo($unknown_base_type);
+        $this->testInlineAdditionalPropertiesWithHttpInfo($UNKNOWN_PARAM_NAME);
     }
 
     /**
@@ -2037,16 +2037,16 @@ class FakeApi
      *
      * test inline additionalProperties
      *
-     * @param  map[string,string] $unknown_base_type request body (required)
+     * @param   $UNKNOWN_PARAM_NAME request body (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function testInlineAdditionalPropertiesWithHttpInfo($unknown_base_type)
+    public function testInlineAdditionalPropertiesWithHttpInfo($UNKNOWN_PARAM_NAME)
     {
         $returnType = '';
-        $request = $this->testInlineAdditionalPropertiesRequest($unknown_base_type);
+        $request = $this->testInlineAdditionalPropertiesRequest($UNKNOWN_PARAM_NAME);
 
         try {
             $options = $this->createHttpClientOption();
@@ -2090,14 +2090,14 @@ class FakeApi
      *
      * test inline additionalProperties
      *
-     * @param  map[string,string] $unknown_base_type request body (required)
+     * @param   $UNKNOWN_PARAM_NAME request body (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testInlineAdditionalPropertiesAsync($unknown_base_type)
+    public function testInlineAdditionalPropertiesAsync($UNKNOWN_PARAM_NAME)
     {
-        return $this->testInlineAdditionalPropertiesAsyncWithHttpInfo($unknown_base_type)
+        return $this->testInlineAdditionalPropertiesAsyncWithHttpInfo($UNKNOWN_PARAM_NAME)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -2110,15 +2110,15 @@ class FakeApi
      *
      * test inline additionalProperties
      *
-     * @param  map[string,string] $unknown_base_type request body (required)
+     * @param   $UNKNOWN_PARAM_NAME request body (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testInlineAdditionalPropertiesAsyncWithHttpInfo($unknown_base_type)
+    public function testInlineAdditionalPropertiesAsyncWithHttpInfo($UNKNOWN_PARAM_NAME)
     {
         $returnType = '';
-        $request = $this->testInlineAdditionalPropertiesRequest($unknown_base_type);
+        $request = $this->testInlineAdditionalPropertiesRequest($UNKNOWN_PARAM_NAME);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -2146,17 +2146,17 @@ class FakeApi
     /**
      * Create request for operation 'testInlineAdditionalProperties'
      *
-     * @param  map[string,string] $unknown_base_type request body (required)
+     * @param   $UNKNOWN_PARAM_NAME request body (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function testInlineAdditionalPropertiesRequest($unknown_base_type)
+    protected function testInlineAdditionalPropertiesRequest($UNKNOWN_PARAM_NAME)
     {
-        // verify the required parameter 'unknown_base_type' is set
-        if ($unknown_base_type === null || (is_array($unknown_base_type) && count($unknown_base_type) === 0)) {
+        // verify the required parameter 'UNKNOWN_PARAM_NAME' is set
+        if ($UNKNOWN_PARAM_NAME === null || (is_array($UNKNOWN_PARAM_NAME) && count($UNKNOWN_PARAM_NAME) === 0)) {
             throw new \InvalidArgumentException(
-                'Missing the required parameter $unknown_base_type when calling testInlineAdditionalProperties'
+                'Missing the required parameter $UNKNOWN_PARAM_NAME when calling testInlineAdditionalProperties'
             );
         }
 
@@ -2171,8 +2171,8 @@ class FakeApi
 
         // body params
         $_tempBody = null;
-        if (isset($unknown_base_type)) {
-            $_tempBody = $unknown_base_type;
+        if (isset($UNKNOWN_PARAM_NAME)) {
+            $_tempBody = $UNKNOWN_PARAM_NAME;
         }
 
         if ($multipart) {
@@ -2241,15 +2241,16 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  Body4 $body4 body4 (optional)
+     * @param  string $param field1 (required)
+     * @param  string $param2 field2 (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return void
      */
-    public function testJsonFormData($body4 = null)
+    public function testJsonFormData($param, $param2)
     {
-        $this->testJsonFormDataWithHttpInfo($body4);
+        $this->testJsonFormDataWithHttpInfo($param, $param2);
     }
 
     /**
@@ -2257,16 +2258,17 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  Body4 $body4 (optional)
+     * @param  string $param field1 (required)
+     * @param  string $param2 field2 (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
      * @return array of null, HTTP status code, HTTP response headers (array of strings)
      */
-    public function testJsonFormDataWithHttpInfo($body4 = null)
+    public function testJsonFormDataWithHttpInfo($param, $param2)
     {
         $returnType = '';
-        $request = $this->testJsonFormDataRequest($body4);
+        $request = $this->testJsonFormDataRequest($param, $param2);
 
         try {
             $options = $this->createHttpClientOption();
@@ -2310,14 +2312,15 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  Body4 $body4 (optional)
+     * @param  string $param field1 (required)
+     * @param  string $param2 field2 (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testJsonFormDataAsync($body4 = null)
+    public function testJsonFormDataAsync($param, $param2)
     {
-        return $this->testJsonFormDataAsyncWithHttpInfo($body4)
+        return $this->testJsonFormDataAsyncWithHttpInfo($param, $param2)
             ->then(
                 function ($response) {
                     return $response[0];
@@ -2330,15 +2333,16 @@ class FakeApi
      *
      * test json serialization of form data
      *
-     * @param  Body4 $body4 (optional)
+     * @param  string $param field1 (required)
+     * @param  string $param2 field2 (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
      */
-    public function testJsonFormDataAsyncWithHttpInfo($body4 = null)
+    public function testJsonFormDataAsyncWithHttpInfo($param, $param2)
     {
         $returnType = '';
-        $request = $this->testJsonFormDataRequest($body4);
+        $request = $this->testJsonFormDataRequest($param, $param2);
 
         return $this->client
             ->sendAsync($request, $this->createHttpClientOption())
@@ -2366,13 +2370,26 @@ class FakeApi
     /**
      * Create request for operation 'testJsonFormData'
      *
-     * @param  Body4 $body4 (optional)
+     * @param  string $param field1 (required)
+     * @param  string $param2 field2 (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
      */
-    protected function testJsonFormDataRequest($body4 = null)
+    protected function testJsonFormDataRequest($param, $param2)
     {
+        // verify the required parameter 'param' is set
+        if ($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 = [];
@@ -2383,11 +2400,16 @@ class FakeApi
 
 
 
+        // form params
+        if ($param !== null) {
+            $formParams['param'] = ObjectSerializer::toFormValue($param);
+        }
+        // form params
+        if ($param2 !== null) {
+            $formParams['param2'] = ObjectSerializer::toFormValue($param2);
+        }
         // body params
         $_tempBody = null;
-        if (isset($body4)) {
-            $_tempBody = $body4;
-        }
 
         if ($multipart) {
             $headers = $this->headerSelector->selectHeadersForMultipart(
@@ -2396,7 +2418,7 @@ class FakeApi
         } else {
             $headers = $this->headerSelector->selectHeaders(
                 [],
-                ['application/json']
+                ['application/x-www-form-urlencoded']
             );
         }
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeClassnameTags123Api.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeClassnameTags123Api.php
index d41810b64b9..578fd4a4ac9 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeClassnameTags123Api.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/FakeClassnameTags123Api.php
@@ -92,7 +92,7 @@ class FakeClassnameTags123Api
      *
      * To test class name in snake case
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -109,7 +109,7 @@ class FakeClassnameTags123Api
      *
      * To test class name in snake case
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -184,7 +184,7 @@ class FakeClassnameTags123Api
      *
      * To test class name in snake case
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -204,7 +204,7 @@ class FakeClassnameTags123Api
      *
      * To test class name in snake case
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -254,7 +254,7 @@ class FakeClassnameTags123Api
     /**
      * Create request for operation 'testClassname'
      *
-     * @param  Client $client client model (required)
+     * @param  \Swagger\Client\Model\Client $client client model (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
index 87f393b2122..fe619dc40e4 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/PetApi.php
@@ -92,7 +92,7 @@ class PetApi
      *
      * Add a new pet to the store
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -108,7 +108,7 @@ class PetApi
      *
      * Add a new pet to the store
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -161,7 +161,7 @@ class PetApi
      *
      * Add a new pet to the store
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -181,7 +181,7 @@ class PetApi
      *
      * Add a new pet to the store
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -217,7 +217,7 @@ class PetApi
     /**
      * Create request for operation 'addPet'
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
@@ -739,7 +739,7 @@ class PetApi
 
         // query params
         if (is_array($status)) {
-            $status = ObjectSerializer::serializeCollection($status, 'multi', true);
+            $status = ObjectSerializer::serializeCollection($status, 'csv', true);
         }
         if ($status !== null) {
             $queryParams['status'] = ObjectSerializer::toQueryValue($status);
@@ -1004,7 +1004,7 @@ class PetApi
 
         // query params
         if (is_array($tags)) {
-            $tags = ObjectSerializer::serializeCollection($tags, 'multi', true);
+            $tags = ObjectSerializer::serializeCollection($tags, 'csv', true);
         }
         if ($tags !== null) {
             $queryParams['tags'] = ObjectSerializer::toQueryValue($tags);
@@ -1351,7 +1351,7 @@ class PetApi
      *
      * Update an existing pet
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -1367,7 +1367,7 @@ class PetApi
      *
      * Update an existing pet
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -1420,7 +1420,7 @@ class PetApi
      *
      * Update an existing pet
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -1440,7 +1440,7 @@ class PetApi
      *
      * Update an existing pet
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -1476,7 +1476,7 @@ class PetApi
     /**
      * Create request for operation 'updatePet'
      *
-     * @param  Pet $pet Pet object that needs to be added to the store (required)
+     * @param  \Swagger\Client\Model\Pet $pet Pet object that needs to be added to the store (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php
index 1cdc67aba3d..664c4bc6baa 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/StoreApi.php
@@ -834,7 +834,7 @@ class StoreApi
      *
      * Place an order for a pet
      *
-     * @param  Order $order order placed for purchasing the pet (required)
+     * @param  \Swagger\Client\Model\Order $order order placed for purchasing the pet (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -851,7 +851,7 @@ class StoreApi
      *
      * Place an order for a pet
      *
-     * @param  Order $order order placed for purchasing the pet (required)
+     * @param  \Swagger\Client\Model\Order $order order placed for purchasing the pet (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -926,7 +926,7 @@ class StoreApi
      *
      * Place an order for a pet
      *
-     * @param  Order $order order placed for purchasing the pet (required)
+     * @param  \Swagger\Client\Model\Order $order order placed for purchasing the pet (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -946,7 +946,7 @@ class StoreApi
      *
      * Place an order for a pet
      *
-     * @param  Order $order order placed for purchasing the pet (required)
+     * @param  \Swagger\Client\Model\Order $order order placed for purchasing the pet (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -996,7 +996,7 @@ class StoreApi
     /**
      * Create request for operation 'placeOrder'
      *
-     * @param  Order $order order placed for purchasing the pet (required)
+     * @param  \Swagger\Client\Model\Order $order order placed for purchasing the pet (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/UserApi.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/UserApi.php
index db186a5357d..0c595d96e61 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/UserApi.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Api/UserApi.php
@@ -92,7 +92,7 @@ class UserApi
      *
      * Create user
      *
-     * @param  User $user Created user object (required)
+     * @param  \Swagger\Client\Model\User $user Created user object (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -108,7 +108,7 @@ class UserApi
      *
      * Create user
      *
-     * @param  User $user Created user object (required)
+     * @param  \Swagger\Client\Model\User $user Created user object (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -161,7 +161,7 @@ class UserApi
      *
      * Create user
      *
-     * @param  User $user Created user object (required)
+     * @param  \Swagger\Client\Model\User $user Created user object (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -181,7 +181,7 @@ class UserApi
      *
      * Create user
      *
-     * @param  User $user Created user object (required)
+     * @param  \Swagger\Client\Model\User $user Created user object (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -217,7 +217,7 @@ class UserApi
     /**
      * Create request for operation 'createUser'
      *
-     * @param  User $user Created user object (required)
+     * @param  \Swagger\Client\Model\User $user Created user object (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
@@ -1719,7 +1719,7 @@ class UserApi
      * Updated user
      *
      * @param  string $username name that need to be deleted (required)
-     * @param  User $user Updated user object (required)
+     * @param  \Swagger\Client\Model\User $user Updated user object (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -1736,7 +1736,7 @@ class UserApi
      * Updated user
      *
      * @param  string $username name that need to be deleted (required)
-     * @param  User $user Updated user object (required)
+     * @param  \Swagger\Client\Model\User $user Updated user object (required)
      *
      * @throws \Swagger\Client\ApiException on non-2xx response
      * @throws \InvalidArgumentException
@@ -1790,7 +1790,7 @@ class UserApi
      * Updated user
      *
      * @param  string $username name that need to be deleted (required)
-     * @param  User $user Updated user object (required)
+     * @param  \Swagger\Client\Model\User $user Updated user object (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -1811,7 +1811,7 @@ class UserApi
      * Updated user
      *
      * @param  string $username name that need to be deleted (required)
-     * @param  User $user Updated user object (required)
+     * @param  \Swagger\Client\Model\User $user Updated user object (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Promise\PromiseInterface
@@ -1848,7 +1848,7 @@ class UserApi
      * Create request for operation 'updateUser'
      *
      * @param  string $username name that need to be deleted (required)
-     * @param  User $user Updated user object (required)
+     * @param  \Swagger\Client\Model\User $user Updated user object (required)
      *
      * @throws \InvalidArgumentException
      * @return \GuzzleHttp\Psr7\Request
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Model/SpecialModelName.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Model/SpecialModelName.php
new file mode 100644
index 00000000000..2324115086e
--- /dev/null
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/lib/Model/SpecialModelName.php
@@ -0,0 +1,302 @@
+<?php
+/**
+ * SpecialModelName
+ *
+ * PHP version 5
+ *
+ * @category Class
+ * @package  Swagger\Client
+ * @author   Swagger Codegen team
+ * @link     https://github.com/swagger-api/swagger-codegen
+ */
+
+/**
+ * Swagger Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * OpenAPI spec version: 1.0.0
+ * Contact: apiteam@swagger.io
+ * Generated by: https://github.com/swagger-api/swagger-codegen.git
+ * Swagger Codegen version: 3.0.0-SNAPSHOT
+ */
+
+/**
+ * NOTE: This class is auto generated by the swagger code generator program.
+ * https://github.com/swagger-api/swagger-codegen
+ * Do not edit the class manually.
+ */
+
+namespace Swagger\Client\Model;
+
+use \ArrayAccess;
+use \Swagger\Client\ObjectSerializer;
+
+/**
+ * SpecialModelName Class Doc Comment
+ *
+ * @category Class
+ * @package  Swagger\Client
+ * @author   Swagger Codegen team
+ * @link     https://github.com/swagger-api/swagger-codegen
+ */
+class SpecialModelName implements ModelInterface, ArrayAccess
+{
+    const DISCRIMINATOR = null;
+
+    /**
+      * The original name of the model.
+      *
+      * @var string
+      */
+    protected static $swaggerModelName = '_special_model.name_';
+
+    /**
+      * Array of property to type mappings. Used for (de)serialization
+      *
+      * @var string[]
+      */
+    protected static $swaggerTypes = [
+        'special_property_name' => 'int'
+    ];
+
+    /**
+      * Array of property to format mappings. Used for (de)serialization
+      *
+      * @var string[]
+      */
+    protected static $swaggerFormats = [
+        'special_property_name' => 'int64'
+    ];
+
+    /**
+     * Array of property to type mappings. Used for (de)serialization
+     *
+     * @return array
+     */
+    public static function swaggerTypes()
+    {
+        return self::$swaggerTypes;
+    }
+
+    /**
+     * Array of property to format mappings. Used for (de)serialization
+     *
+     * @return array
+     */
+    public static function swaggerFormats()
+    {
+        return self::$swaggerFormats;
+    }
+
+    /**
+     * Array of attributes where the key is the local name,
+     * and the value is the original name
+     *
+     * @var string[]
+     */
+    protected static $attributeMap = [
+        'special_property_name' => '$special[property.name]'
+    ];
+
+    /**
+     * Array of attributes to setter functions (for deserialization of responses)
+     *
+     * @var string[]
+     */
+    protected static $setters = [
+        'special_property_name' => 'setSpecialPropertyName'
+    ];
+
+    /**
+     * Array of attributes to getter functions (for serialization of requests)
+     *
+     * @var string[]
+     */
+    protected static $getters = [
+        'special_property_name' => 'getSpecialPropertyName'
+    ];
+
+    /**
+     * Array of attributes where the key is the local name,
+     * and the value is the original name
+     *
+     * @return array
+     */
+    public static function attributeMap()
+    {
+        return self::$attributeMap;
+    }
+
+    /**
+     * Array of attributes to setter functions (for deserialization of responses)
+     *
+     * @return array
+     */
+    public static function setters()
+    {
+        return self::$setters;
+    }
+
+    /**
+     * Array of attributes to getter functions (for serialization of requests)
+     *
+     * @return array
+     */
+    public static function getters()
+    {
+        return self::$getters;
+    }
+
+    /**
+     * The original name of the model.
+     *
+     * @return string
+     */
+    public function getModelName()
+    {
+        return self::$swaggerModelName;
+    }
+
+    
+
+    
+
+    /**
+     * Associative array for storing property values
+     *
+     * @var mixed[]
+     */
+    protected $container = [];
+
+    /**
+     * Constructor
+     *
+     * @param mixed[] $data Associated array of property values
+     *                      initializing the model
+     */
+    public function __construct(array $data = null)
+    {
+        $this->container['special_property_name'] = isset($data['special_property_name']) ? $data['special_property_name'] : null;
+    }
+
+    /**
+     * Show all the invalid properties with reasons.
+     *
+     * @return array invalid properties with reasons
+     */
+    public function listInvalidProperties()
+    {
+        $invalidProperties = [];
+
+        return $invalidProperties;
+    }
+
+    /**
+     * Validate all the properties in the model
+     * return true if all passed
+     *
+     * @return bool True if all properties are valid
+     */
+    public function valid()
+    {
+
+        return true;
+    }
+
+
+    /**
+     * Gets special_property_name
+     *
+     * @return int
+     */
+    public function getSpecialPropertyName()
+    {
+        return $this->container['special_property_name'];
+    }
+
+    /**
+     * Sets special_property_name
+     *
+     * @param int $special_property_name special_property_name
+     *
+     * @return $this
+     */
+    public function setSpecialPropertyName($special_property_name)
+    {
+        $this->container['special_property_name'] = $special_property_name;
+
+        return $this;
+    }
+    /**
+     * Returns true if offset exists. False otherwise.
+     *
+     * @param integer $offset Offset
+     *
+     * @return boolean
+     */
+    public function offsetExists($offset)
+    {
+        return isset($this->container[$offset]);
+    }
+
+    /**
+     * Gets offset.
+     *
+     * @param integer $offset Offset
+     *
+     * @return mixed
+     */
+    public function offsetGet($offset)
+    {
+        return isset($this->container[$offset]) ? $this->container[$offset] : null;
+    }
+
+    /**
+     * Sets value based on offset.
+     *
+     * @param integer $offset Offset
+     * @param mixed   $value  Value to be set
+     *
+     * @return void
+     */
+    public function offsetSet($offset, $value)
+    {
+        if (is_null($offset)) {
+            $this->container[] = $value;
+        } else {
+            $this->container[$offset] = $value;
+        }
+    }
+
+    /**
+     * Unsets offset.
+     *
+     * @param integer $offset Offset
+     *
+     * @return void
+     */
+    public function offsetUnset($offset)
+    {
+        unset($this->container[$offset]);
+    }
+
+    /**
+     * Gets the string presentation of the object
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        if (defined('JSON_PRETTY_PRINT')) { // use JSON pretty print
+            return json_encode(
+                ObjectSerializer::sanitizeForSerialization($this),
+                JSON_PRETTY_PRINT
+            );
+        }
+
+        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
+    }
+}
+
+
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/Body4Test.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/Body4Test.php
deleted file mode 100644
index 66a696fd4ed..00000000000
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/Body4Test.php
+++ /dev/null
@@ -1,92 +0,0 @@
-<?php
-/**
- * Body4Test
- *
- * PHP version 5
- *
- * @category Class
- * @package  Swagger\Client
- * @author   Swagger Codegen team
- * @link     https://github.com/swagger-api/swagger-codegen
- */
-
-/**
- * Swagger Petstore
- *
- * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
- *
- * OpenAPI spec version: 1.0.0
- * Contact: apiteam@swagger.io
- * Generated by: https://github.com/swagger-api/swagger-codegen.git
- * Swagger Codegen version: 3.0.0-SNAPSHOT
- */
-
-/**
- * NOTE: This class is auto generated by the swagger code generator program.
- * https://github.com/swagger-api/swagger-codegen
- * Please update the test case below to test the model.
- */
-
-namespace Swagger\Client;
-
-/**
- * Body4Test Class Doc Comment
- *
- * @category    Class
- * @description Body4
- * @package     Swagger\Client
- * @author      Swagger Codegen team
- * @link        https://github.com/swagger-api/swagger-codegen
- */
-class Body4Test extends \PHPUnit_Framework_TestCase
-{
-
-    /**
-     * Setup before running any test case
-     */
-    public static function setUpBeforeClass()
-    {
-    }
-
-    /**
-     * Setup before running each test case
-     */
-    public function setUp()
-    {
-    }
-
-    /**
-     * Clean up after running each test case
-     */
-    public function tearDown()
-    {
-    }
-
-    /**
-     * Clean up after running all test cases
-     */
-    public static function tearDownAfterClass()
-    {
-    }
-
-    /**
-     * Test "Body4"
-     */
-    public function testBody4()
-    {
-    }
-
-    /**
-     * Test attribute "param"
-     */
-    public function testPropertyParam()
-    {
-    }
-
-    /**
-     * Test attribute "param2"
-     */
-    public function testPropertyParam2()
-    {
-    }
-}
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/SpecialModelName_Test.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/SpecialModelNameTest.php
similarity index 86%
rename from samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/SpecialModelName_Test.php
rename to samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/SpecialModelNameTest.php
index 973bc90320d..26b60bfde75 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/SpecialModelName_Test.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/test/Model/SpecialModelNameTest.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * SpecialModelName_Test
+ * SpecialModelNameTest
  *
  * PHP version 5
  *
@@ -30,15 +30,15 @@
 namespace Swagger\Client;
 
 /**
- * SpecialModelName_Test Class Doc Comment
+ * SpecialModelNameTest Class Doc Comment
  *
  * @category    Class
- * @description SpecialModelName_
+ * @description SpecialModelName
  * @package     Swagger\Client
  * @author      Swagger Codegen team
  * @link        https://github.com/swagger-api/swagger-codegen
  */
-class SpecialModelName_Test extends \PHPUnit_Framework_TestCase
+class SpecialModelNameTest extends \PHPUnit_Framework_TestCase
 {
 
     /**
@@ -70,9 +70,9 @@ class SpecialModelName_Test extends \PHPUnit_Framework_TestCase
     }
 
     /**
-     * Test "SpecialModelName_"
+     * Test "SpecialModelName"
      */
-    public function testSpecialModelName_()
+    public function testSpecialModelName()
     {
     }
 
diff --git a/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php b/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php
index 2fd9ab8831f..6305798da86 100644
--- a/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php
+++ b/samples/openapi3/client/petstore/php/SwaggerClient-php/tests/RequestTest.php
@@ -22,22 +22,15 @@ class RequestTest extends \PHPUnit_Framework_TestCase
 
     public function testFormDataEncodingToJson()
     {
-        $this->api->testJsonFormData(
-            new Body4(['param' => 'value', 'param2' => 'value2'])
-        );
+        $this->api->testJsonFormData('value', 'value2');
 
         $request = $this->fakeClient->getLastRequest();
         $contentType = $request->getHeader('Content-Type');
-        $this->assertEquals(['application/json'], $contentType);
+        $this->assertEquals(['application/x-www-form-urlencoded'], $contentType);
 
         $requestContent = $request->getBody()->getContents();
-        $expected = <<<__EOS__
-{
-    "param": "value",
-    "param2": "value2"
-}
-__EOS__;
 
-        $this->assertEquals($expected, $requestContent);
+        // JSON serialization of form data is not supported
+        $this->assertEquals('param=value&param2=value2', $requestContent);
     }
 }