diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java
index 40d986a66504..16930ee127ef 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java
@@ -18,6 +18,7 @@
 
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.oas.models.media.StringSchema;
+import io.swagger.v3.oas.models.parameters.Parameter;
 import lombok.Getter;
 import lombok.Setter;
 import org.apache.commons.io.FilenameUtils;
@@ -384,6 +385,11 @@ public String getTypeDeclaration(String name) {
         return super.getTypeDeclaration(name);
     }
 
+    @Override
+    protected String getParameterDataType(Parameter parameter, Schema schema) {
+        return getTypeDeclaration(schema);
+    }
+
     @Override
     public String getSchemaType(Schema p) {
         String openAPIType = super.getSchemaType(p);
diff --git a/modules/openapi-generator/src/test/resources/3_0/php-nextgen/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/php-nextgen/petstore-with-fake-endpoints-models-for-testing.yaml
index cebc271e1d5b..81e7a7ca407d 100644
--- a/modules/openapi-generator/src/test/resources/3_0/php-nextgen/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/php-nextgen/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -1303,6 +1303,42 @@ paths:
       responses:
         200:
           description: The instance started successfully
+  /fake/enum/endpoint:
+    get:
+      tags:
+        - fake
+      summary: test endpoint with enum parameter
+      operationId: fake-enum-endpoint
+      parameters:
+        - name: enum-class
+          in: query
+          description: enum class parameter
+          required: true
+          schema:
+              $ref: '#/components/schemas/EnumClass'
+        - name: enum-class-array
+          in: query
+          description: enum class parameter
+          required: true
+          schema:
+            type: array
+            items:
+              $ref: '#/components/schemas/EnumClass'
+        - name: enum-class-map
+          in: query
+          description: enum class parameter
+          required: true
+          schema:
+            type: object
+            additionalProperties:
+              $ref: '#/components/schemas/EnumClass'
+      responses:
+        200:
+          description: The instance started successfully
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/EnumClass'
 servers:
   - url: 'http://{server}.swagger.io:{port}/v2'
     description: petstore server
diff --git a/modules/openapi-generator/src/test/resources/3_0/php/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/php/petstore-with-fake-endpoints-models-for-testing.yaml
index 138e51a2f208..d9e47ca9ed8d 100644
--- a/modules/openapi-generator/src/test/resources/3_0/php/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/php/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -1327,6 +1327,42 @@ paths:
       responses:
         200:
           description: OK
+  /fake/enum/endpoint:
+    get:
+      tags:
+        - fake
+      summary: test endpoint with enum parameter
+      operationId: fake-enum-endpoint
+      parameters:
+        - name: enum-class
+          in: query
+          description: enum class parameter
+          required: true
+          schema:
+            $ref: '#/components/schemas/EnumClass'
+        - name: enum-class-array
+          in: query
+          description: enum class parameter
+          required: true
+          schema:
+            type: array
+            items:
+              $ref: '#/components/schemas/EnumClass'
+        - name: enum-class-map
+          in: query
+          description: enum class parameter
+          required: true
+          schema:
+            type: object
+            additionalProperties:
+              $ref: '#/components/schemas/EnumClass'
+      responses:
+        200:
+          description: The instance started successfully
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/EnumClass'
 servers:
   - url: 'http://{server}.swagger.io:{port}/v2'
     description: petstore server
diff --git a/samples/client/echo_api/php-nextgen-streaming/docs/Api/HeaderApi.md b/samples/client/echo_api/php-nextgen-streaming/docs/Api/HeaderApi.md
index 62de1378949d..d13c2d2ea7be 100644
--- a/samples/client/echo_api/php-nextgen-streaming/docs/Api/HeaderApi.md
+++ b/samples/client/echo_api/php-nextgen-streaming/docs/Api/HeaderApi.md
@@ -34,7 +34,7 @@ $integer_header = 56; // int
 $boolean_header = True; // bool
 $string_header = 'string_header_example'; // string
 $enum_nonref_string_header = 'enum_nonref_string_header_example'; // string
-$enum_ref_string_header = new \OpenAPI\Client\Model\StringEnumRef(); // StringEnumRef
+$enum_ref_string_header = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\StringEnumRef(); // \OpenAPI\Client\Model\StringEnumRef
 
 try {
     $result = $apiInstance->testHeaderIntegerBooleanStringEnums($integer_header, $boolean_header, $string_header, $enum_nonref_string_header, $enum_ref_string_header);
@@ -52,7 +52,7 @@ try {
 | **boolean_header** | **bool**|  | [optional] |
 | **string_header** | **string**|  | [optional] |
 | **enum_nonref_string_header** | **string**|  | [optional] |
-| **enum_ref_string_header** | [**StringEnumRef**](../Model/.md)|  | [optional] |
+| **enum_ref_string_header** | [**\OpenAPI\Client\Model\StringEnumRef**](../Model/.md)|  | [optional] |
 
 ### Return type
 
diff --git a/samples/client/echo_api/php-nextgen-streaming/docs/Api/PathApi.md b/samples/client/echo_api/php-nextgen-streaming/docs/Api/PathApi.md
index 9d3001f01390..45583fd7edd9 100644
--- a/samples/client/echo_api/php-nextgen-streaming/docs/Api/PathApi.md
+++ b/samples/client/echo_api/php-nextgen-streaming/docs/Api/PathApi.md
@@ -33,7 +33,7 @@ $apiInstance = new OpenAPI\Client\Api\PathApi(
 $path_string = 'path_string_example'; // string
 $path_integer = 56; // int
 $enum_nonref_string_path = 'enum_nonref_string_path_example'; // string
-$enum_ref_string_path = new \OpenAPI\Client\Model\StringEnumRef(); // StringEnumRef
+$enum_ref_string_path = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\StringEnumRef(); // \OpenAPI\Client\Model\StringEnumRef
 
 try {
     $result = $apiInstance->testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath($path_string, $path_integer, $enum_nonref_string_path, $enum_ref_string_path);
@@ -50,7 +50,7 @@ try {
 | **path_string** | **string**|  | |
 | **path_integer** | **int**|  | |
 | **enum_nonref_string_path** | **string**|  | |
-| **enum_ref_string_path** | [**StringEnumRef**](../Model/.md)|  | |
+| **enum_ref_string_path** | [**\OpenAPI\Client\Model\StringEnumRef**](../Model/.md)|  | |
 
 ### Return type
 
diff --git a/samples/client/echo_api/php-nextgen-streaming/docs/Api/QueryApi.md b/samples/client/echo_api/php-nextgen-streaming/docs/Api/QueryApi.md
index 10208136e80f..7e1a9f372b8e 100644
--- a/samples/client/echo_api/php-nextgen-streaming/docs/Api/QueryApi.md
+++ b/samples/client/echo_api/php-nextgen-streaming/docs/Api/QueryApi.md
@@ -40,7 +40,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     new GuzzleHttp\Client()
 );
 $enum_nonref_string_query = 'enum_nonref_string_query_example'; // string
-$enum_ref_string_query = new \OpenAPI\Client\Model\StringEnumRef(); // StringEnumRef
+$enum_ref_string_query = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\StringEnumRef(); // \OpenAPI\Client\Model\StringEnumRef
 
 try {
     $result = $apiInstance->testEnumRefString($enum_nonref_string_query, $enum_ref_string_query);
@@ -55,7 +55,7 @@ try {
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
 | **enum_nonref_string_query** | **string**|  | [optional] |
-| **enum_ref_string_query** | [**StringEnumRef**](../Model/.md)|  | [optional] |
+| **enum_ref_string_query** | [**\OpenAPI\Client\Model\StringEnumRef**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -217,7 +217,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\Pet(); // Pet
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\Pet(); // \OpenAPI\Client\Model\Pet
 
 try {
     $result = $apiInstance->testQueryStyleDeepObjectExplodeTrueObject($query_object);
@@ -231,7 +231,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**Pet**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\Pet**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -273,7 +273,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter(); // TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter(); // \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter
 
 try {
     $result = $apiInstance->testQueryStyleDeepObjectExplodeTrueObjectAllOf($query_object);
@@ -287,7 +287,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -441,7 +441,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter(); // TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter(); // \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter
 
 try {
     $result = $apiInstance->testQueryStyleFormExplodeTrueArrayString($query_object);
@@ -455,7 +455,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -497,7 +497,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\Pet(); // Pet
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\Pet(); // \OpenAPI\Client\Model\Pet
 
 try {
     $result = $apiInstance->testQueryStyleFormExplodeTrueObject($query_object);
@@ -511,7 +511,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**Pet**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\Pet**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -553,7 +553,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\DataQuery(); // DataQuery
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\DataQuery(); // \OpenAPI\Client\Model\DataQuery
 
 try {
     $result = $apiInstance->testQueryStyleFormExplodeTrueObjectAllOf($query_object);
@@ -567,7 +567,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**DataQuery**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\DataQuery**](../Model/.md)|  | [optional] |
 
 ### Return type
 
diff --git a/samples/client/echo_api/php-nextgen-streaming/src/Api/HeaderApi.php b/samples/client/echo_api/php-nextgen-streaming/src/Api/HeaderApi.php
index 6465a1b3ba45..7c5f591dfbda 100644
--- a/samples/client/echo_api/php-nextgen-streaming/src/Api/HeaderApi.php
+++ b/samples/client/echo_api/php-nextgen-streaming/src/Api/HeaderApi.php
@@ -132,7 +132,7 @@ public function getConfig(): Configuration
      * @param  bool|null $boolean_header boolean_header (optional)
      * @param  string|null $string_header string_header (optional)
      * @param  string|null $enum_nonref_string_header enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -144,7 +144,7 @@ public function testHeaderIntegerBooleanStringEnums(
         ?bool $boolean_header = null,
         ?string $string_header = null,
         ?string $enum_nonref_string_header = null,
-        ?StringEnumRef $enum_ref_string_header = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_header = null,
         string $contentType = self::contentTypes['testHeaderIntegerBooleanStringEnums'][0]
     ): string
     {
@@ -161,7 +161,7 @@ public function testHeaderIntegerBooleanStringEnums(
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -173,7 +173,7 @@ public function testHeaderIntegerBooleanStringEnumsWithHttpInfo(
         ?bool $boolean_header = null,
         ?string $string_header = null,
         ?string $enum_nonref_string_header = null,
-        ?StringEnumRef $enum_ref_string_header = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_header = null,
         string $contentType = self::contentTypes['testHeaderIntegerBooleanStringEnums'][0]
     ): array
     {
@@ -296,7 +296,7 @@ public function testHeaderIntegerBooleanStringEnumsWithHttpInfo(
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -307,7 +307,7 @@ public function testHeaderIntegerBooleanStringEnumsAsync(
         ?bool $boolean_header = null,
         ?string $string_header = null,
         ?string $enum_nonref_string_header = null,
-        ?StringEnumRef $enum_ref_string_header = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_header = null,
         string $contentType = self::contentTypes['testHeaderIntegerBooleanStringEnums'][0]
     ): PromiseInterface
     {
@@ -328,7 +328,7 @@ function ($response) {
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -389,7 +389,7 @@ function ($exception) {
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
diff --git a/samples/client/echo_api/php-nextgen-streaming/src/Api/PathApi.php b/samples/client/echo_api/php-nextgen-streaming/src/Api/PathApi.php
index dbeb47e3dde3..fe13acc0c43f 100644
--- a/samples/client/echo_api/php-nextgen-streaming/src/Api/PathApi.php
+++ b/samples/client/echo_api/php-nextgen-streaming/src/Api/PathApi.php
@@ -131,7 +131,7 @@ public function getConfig(): Configuration
      * @param  string $path_string path_string (required)
      * @param  int $path_integer path_integer (required)
      * @param  string $enum_nonref_string_path enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -142,7 +142,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
         string $path_string,
         int $path_integer,
         string $enum_nonref_string_path,
-        StringEnumRef $enum_ref_string_path,
+        \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path,
         string $contentType = self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'][0]
     ): string
     {
@@ -158,7 +158,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -169,7 +169,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
         string $path_string,
         int $path_integer,
         string $enum_nonref_string_path,
-        StringEnumRef $enum_ref_string_path,
+        \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path,
         string $contentType = self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'][0]
     ): array
     {
@@ -291,7 +291,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -301,7 +301,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
         string $path_string,
         int $path_integer,
         string $enum_nonref_string_path,
-        StringEnumRef $enum_ref_string_path,
+        \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path,
         string $contentType = self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'][0]
     ): PromiseInterface
     {
@@ -321,7 +321,7 @@ function ($response) {
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -380,7 +380,7 @@ function ($exception) {
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
diff --git a/samples/client/echo_api/php-nextgen-streaming/src/Api/QueryApi.php b/samples/client/echo_api/php-nextgen-streaming/src/Api/QueryApi.php
index ca420cea4f22..98ab9b319efb 100644
--- a/samples/client/echo_api/php-nextgen-streaming/src/Api/QueryApi.php
+++ b/samples/client/echo_api/php-nextgen-streaming/src/Api/QueryApi.php
@@ -156,7 +156,7 @@ public function getConfig(): Configuration
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -165,7 +165,7 @@ public function getConfig(): Configuration
      */
     public function testEnumRefString(
         ?string $enum_nonref_string_query = null,
-        ?StringEnumRef $enum_ref_string_query = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_query = null,
         string $contentType = self::contentTypes['testEnumRefString'][0]
     ): string
     {
@@ -179,7 +179,7 @@ public function testEnumRefString(
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -188,7 +188,7 @@ public function testEnumRefString(
      */
     public function testEnumRefStringWithHttpInfo(
         ?string $enum_nonref_string_query = null,
-        ?StringEnumRef $enum_ref_string_query = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_query = null,
         string $contentType = self::contentTypes['testEnumRefString'][0]
     ): array
     {
@@ -308,7 +308,7 @@ public function testEnumRefStringWithHttpInfo(
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -316,7 +316,7 @@ public function testEnumRefStringWithHttpInfo(
      */
     public function testEnumRefStringAsync(
         ?string $enum_nonref_string_query = null,
-        ?StringEnumRef $enum_ref_string_query = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_query = null,
         string $contentType = self::contentTypes['testEnumRefString'][0]
     ): PromiseInterface
     {
@@ -334,7 +334,7 @@ function ($response) {
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -389,7 +389,7 @@ function ($exception) {
      * Create request for operation 'testEnumRefString'
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1206,7 +1206,7 @@ public function testQueryIntegerBooleanStringRequest(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1214,7 +1214,7 @@ public function testQueryIntegerBooleanStringRequest(
      * @return string
      */
     public function testQueryStyleDeepObjectExplodeTrueObject(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'][0]
     ): string
     {
@@ -1227,7 +1227,7 @@ public function testQueryStyleDeepObjectExplodeTrueObject(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1235,7 +1235,7 @@ public function testQueryStyleDeepObjectExplodeTrueObject(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectWithHttpInfo(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'][0]
     ): array
     {
@@ -1354,14 +1354,14 @@ public function testQueryStyleDeepObjectExplodeTrueObjectWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAsync(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'][0]
     ): PromiseInterface
     {
@@ -1378,7 +1378,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1431,7 +1431,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleDeepObjectExplodeTrueObject'
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1523,7 +1523,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectRequest(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1531,7 +1531,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectRequest(
      * @return string
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAllOf(
-        ?TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'][0]
     ): string
     {
@@ -1544,7 +1544,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectAllOf(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1552,7 +1552,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectAllOf(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAllOfWithHttpInfo(
-        ?TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'][0]
     ): array
     {
@@ -1671,14 +1671,14 @@ public function testQueryStyleDeepObjectExplodeTrueObjectAllOfWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAllOfAsync(
-        ?TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'][0]
     ): PromiseInterface
     {
@@ -1695,7 +1695,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1748,7 +1748,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleDeepObjectExplodeTrueObjectAllOf'
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -2474,7 +2474,7 @@ public function testQueryStyleFormExplodeFalseArrayStringRequest(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2482,7 +2482,7 @@ public function testQueryStyleFormExplodeFalseArrayStringRequest(
      * @return string
      */
     public function testQueryStyleFormExplodeTrueArrayString(
-        ?TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueArrayString'][0]
     ): string
     {
@@ -2495,7 +2495,7 @@ public function testQueryStyleFormExplodeTrueArrayString(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2503,7 +2503,7 @@ public function testQueryStyleFormExplodeTrueArrayString(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleFormExplodeTrueArrayStringWithHttpInfo(
-        ?TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueArrayString'][0]
     ): array
     {
@@ -2622,14 +2622,14 @@ public function testQueryStyleFormExplodeTrueArrayStringWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleFormExplodeTrueArrayStringAsync(
-        ?TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueArrayString'][0]
     ): PromiseInterface
     {
@@ -2646,7 +2646,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -2699,7 +2699,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleFormExplodeTrueArrayString'
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -2791,7 +2791,7 @@ public function testQueryStyleFormExplodeTrueArrayStringRequest(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2799,7 +2799,7 @@ public function testQueryStyleFormExplodeTrueArrayStringRequest(
      * @return string
      */
     public function testQueryStyleFormExplodeTrueObject(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObject'][0]
     ): string
     {
@@ -2812,7 +2812,7 @@ public function testQueryStyleFormExplodeTrueObject(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2820,7 +2820,7 @@ public function testQueryStyleFormExplodeTrueObject(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleFormExplodeTrueObjectWithHttpInfo(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObject'][0]
     ): array
     {
@@ -2939,14 +2939,14 @@ public function testQueryStyleFormExplodeTrueObjectWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleFormExplodeTrueObjectAsync(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObject'][0]
     ): PromiseInterface
     {
@@ -2963,7 +2963,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -3016,7 +3016,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleFormExplodeTrueObject'
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -3108,7 +3108,7 @@ public function testQueryStyleFormExplodeTrueObjectRequest(
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -3116,7 +3116,7 @@ public function testQueryStyleFormExplodeTrueObjectRequest(
      * @return string
      */
     public function testQueryStyleFormExplodeTrueObjectAllOf(
-        ?DataQuery $query_object = null,
+        ?\OpenAPI\Client\Model\DataQuery $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'][0]
     ): string
     {
@@ -3129,7 +3129,7 @@ public function testQueryStyleFormExplodeTrueObjectAllOf(
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -3137,7 +3137,7 @@ public function testQueryStyleFormExplodeTrueObjectAllOf(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleFormExplodeTrueObjectAllOfWithHttpInfo(
-        ?DataQuery $query_object = null,
+        ?\OpenAPI\Client\Model\DataQuery $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'][0]
     ): array
     {
@@ -3256,14 +3256,14 @@ public function testQueryStyleFormExplodeTrueObjectAllOfWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleFormExplodeTrueObjectAllOfAsync(
-        ?DataQuery $query_object = null,
+        ?\OpenAPI\Client\Model\DataQuery $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'][0]
     ): PromiseInterface
     {
@@ -3280,7 +3280,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -3333,7 +3333,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleFormExplodeTrueObjectAllOf'
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
diff --git a/samples/client/echo_api/php-nextgen/docs/Api/HeaderApi.md b/samples/client/echo_api/php-nextgen/docs/Api/HeaderApi.md
index 62de1378949d..d13c2d2ea7be 100644
--- a/samples/client/echo_api/php-nextgen/docs/Api/HeaderApi.md
+++ b/samples/client/echo_api/php-nextgen/docs/Api/HeaderApi.md
@@ -34,7 +34,7 @@ $integer_header = 56; // int
 $boolean_header = True; // bool
 $string_header = 'string_header_example'; // string
 $enum_nonref_string_header = 'enum_nonref_string_header_example'; // string
-$enum_ref_string_header = new \OpenAPI\Client\Model\StringEnumRef(); // StringEnumRef
+$enum_ref_string_header = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\StringEnumRef(); // \OpenAPI\Client\Model\StringEnumRef
 
 try {
     $result = $apiInstance->testHeaderIntegerBooleanStringEnums($integer_header, $boolean_header, $string_header, $enum_nonref_string_header, $enum_ref_string_header);
@@ -52,7 +52,7 @@ try {
 | **boolean_header** | **bool**|  | [optional] |
 | **string_header** | **string**|  | [optional] |
 | **enum_nonref_string_header** | **string**|  | [optional] |
-| **enum_ref_string_header** | [**StringEnumRef**](../Model/.md)|  | [optional] |
+| **enum_ref_string_header** | [**\OpenAPI\Client\Model\StringEnumRef**](../Model/.md)|  | [optional] |
 
 ### Return type
 
diff --git a/samples/client/echo_api/php-nextgen/docs/Api/PathApi.md b/samples/client/echo_api/php-nextgen/docs/Api/PathApi.md
index 9d3001f01390..45583fd7edd9 100644
--- a/samples/client/echo_api/php-nextgen/docs/Api/PathApi.md
+++ b/samples/client/echo_api/php-nextgen/docs/Api/PathApi.md
@@ -33,7 +33,7 @@ $apiInstance = new OpenAPI\Client\Api\PathApi(
 $path_string = 'path_string_example'; // string
 $path_integer = 56; // int
 $enum_nonref_string_path = 'enum_nonref_string_path_example'; // string
-$enum_ref_string_path = new \OpenAPI\Client\Model\StringEnumRef(); // StringEnumRef
+$enum_ref_string_path = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\StringEnumRef(); // \OpenAPI\Client\Model\StringEnumRef
 
 try {
     $result = $apiInstance->testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath($path_string, $path_integer, $enum_nonref_string_path, $enum_ref_string_path);
@@ -50,7 +50,7 @@ try {
 | **path_string** | **string**|  | |
 | **path_integer** | **int**|  | |
 | **enum_nonref_string_path** | **string**|  | |
-| **enum_ref_string_path** | [**StringEnumRef**](../Model/.md)|  | |
+| **enum_ref_string_path** | [**\OpenAPI\Client\Model\StringEnumRef**](../Model/.md)|  | |
 
 ### Return type
 
diff --git a/samples/client/echo_api/php-nextgen/docs/Api/QueryApi.md b/samples/client/echo_api/php-nextgen/docs/Api/QueryApi.md
index 10208136e80f..7e1a9f372b8e 100644
--- a/samples/client/echo_api/php-nextgen/docs/Api/QueryApi.md
+++ b/samples/client/echo_api/php-nextgen/docs/Api/QueryApi.md
@@ -40,7 +40,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     new GuzzleHttp\Client()
 );
 $enum_nonref_string_query = 'enum_nonref_string_query_example'; // string
-$enum_ref_string_query = new \OpenAPI\Client\Model\StringEnumRef(); // StringEnumRef
+$enum_ref_string_query = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\StringEnumRef(); // \OpenAPI\Client\Model\StringEnumRef
 
 try {
     $result = $apiInstance->testEnumRefString($enum_nonref_string_query, $enum_ref_string_query);
@@ -55,7 +55,7 @@ try {
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
 | **enum_nonref_string_query** | **string**|  | [optional] |
-| **enum_ref_string_query** | [**StringEnumRef**](../Model/.md)|  | [optional] |
+| **enum_ref_string_query** | [**\OpenAPI\Client\Model\StringEnumRef**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -217,7 +217,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\Pet(); // Pet
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\Pet(); // \OpenAPI\Client\Model\Pet
 
 try {
     $result = $apiInstance->testQueryStyleDeepObjectExplodeTrueObject($query_object);
@@ -231,7 +231,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**Pet**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\Pet**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -273,7 +273,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter(); // TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter(); // \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter
 
 try {
     $result = $apiInstance->testQueryStyleDeepObjectExplodeTrueObjectAllOf($query_object);
@@ -287,7 +287,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -441,7 +441,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter(); // TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter(); // \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter
 
 try {
     $result = $apiInstance->testQueryStyleFormExplodeTrueArrayString($query_object);
@@ -455,7 +455,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -497,7 +497,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\Pet(); // Pet
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\Pet(); // \OpenAPI\Client\Model\Pet
 
 try {
     $result = $apiInstance->testQueryStyleFormExplodeTrueObject($query_object);
@@ -511,7 +511,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**Pet**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\Pet**](../Model/.md)|  | [optional] |
 
 ### Return type
 
@@ -553,7 +553,7 @@ $apiInstance = new OpenAPI\Client\Api\QueryApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
-$query_object = new \OpenAPI\Client\Model\DataQuery(); // DataQuery
+$query_object = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\DataQuery(); // \OpenAPI\Client\Model\DataQuery
 
 try {
     $result = $apiInstance->testQueryStyleFormExplodeTrueObjectAllOf($query_object);
@@ -567,7 +567,7 @@ try {
 
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **query_object** | [**DataQuery**](../Model/.md)|  | [optional] |
+| **query_object** | [**\OpenAPI\Client\Model\DataQuery**](../Model/.md)|  | [optional] |
 
 ### Return type
 
diff --git a/samples/client/echo_api/php-nextgen/src/Api/HeaderApi.php b/samples/client/echo_api/php-nextgen/src/Api/HeaderApi.php
index 6465a1b3ba45..7c5f591dfbda 100644
--- a/samples/client/echo_api/php-nextgen/src/Api/HeaderApi.php
+++ b/samples/client/echo_api/php-nextgen/src/Api/HeaderApi.php
@@ -132,7 +132,7 @@ public function getConfig(): Configuration
      * @param  bool|null $boolean_header boolean_header (optional)
      * @param  string|null $string_header string_header (optional)
      * @param  string|null $enum_nonref_string_header enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -144,7 +144,7 @@ public function testHeaderIntegerBooleanStringEnums(
         ?bool $boolean_header = null,
         ?string $string_header = null,
         ?string $enum_nonref_string_header = null,
-        ?StringEnumRef $enum_ref_string_header = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_header = null,
         string $contentType = self::contentTypes['testHeaderIntegerBooleanStringEnums'][0]
     ): string
     {
@@ -161,7 +161,7 @@ public function testHeaderIntegerBooleanStringEnums(
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -173,7 +173,7 @@ public function testHeaderIntegerBooleanStringEnumsWithHttpInfo(
         ?bool $boolean_header = null,
         ?string $string_header = null,
         ?string $enum_nonref_string_header = null,
-        ?StringEnumRef $enum_ref_string_header = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_header = null,
         string $contentType = self::contentTypes['testHeaderIntegerBooleanStringEnums'][0]
     ): array
     {
@@ -296,7 +296,7 @@ public function testHeaderIntegerBooleanStringEnumsWithHttpInfo(
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -307,7 +307,7 @@ public function testHeaderIntegerBooleanStringEnumsAsync(
         ?bool $boolean_header = null,
         ?string $string_header = null,
         ?string $enum_nonref_string_header = null,
-        ?StringEnumRef $enum_ref_string_header = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_header = null,
         string $contentType = self::contentTypes['testHeaderIntegerBooleanStringEnums'][0]
     ): PromiseInterface
     {
@@ -328,7 +328,7 @@ function ($response) {
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -389,7 +389,7 @@ function ($exception) {
      * @param  bool|null $boolean_header (optional)
      * @param  string|null $string_header (optional)
      * @param  string|null $enum_nonref_string_header (optional)
-     * @param  StringEnumRef|null $enum_ref_string_header (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_header (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testHeaderIntegerBooleanStringEnums'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
diff --git a/samples/client/echo_api/php-nextgen/src/Api/PathApi.php b/samples/client/echo_api/php-nextgen/src/Api/PathApi.php
index dbeb47e3dde3..fe13acc0c43f 100644
--- a/samples/client/echo_api/php-nextgen/src/Api/PathApi.php
+++ b/samples/client/echo_api/php-nextgen/src/Api/PathApi.php
@@ -131,7 +131,7 @@ public function getConfig(): Configuration
      * @param  string $path_string path_string (required)
      * @param  int $path_integer path_integer (required)
      * @param  string $enum_nonref_string_path enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -142,7 +142,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
         string $path_string,
         int $path_integer,
         string $enum_nonref_string_path,
-        StringEnumRef $enum_ref_string_path,
+        \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path,
         string $contentType = self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'][0]
     ): string
     {
@@ -158,7 +158,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -169,7 +169,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
         string $path_string,
         int $path_integer,
         string $enum_nonref_string_path,
-        StringEnumRef $enum_ref_string_path,
+        \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path,
         string $contentType = self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'][0]
     ): array
     {
@@ -291,7 +291,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -301,7 +301,7 @@ public function testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathE
         string $path_string,
         int $path_integer,
         string $enum_nonref_string_path,
-        StringEnumRef $enum_ref_string_path,
+        \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path,
         string $contentType = self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'][0]
     ): PromiseInterface
     {
@@ -321,7 +321,7 @@ function ($response) {
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -380,7 +380,7 @@ function ($exception) {
      * @param  string $path_string (required)
      * @param  int $path_integer (required)
      * @param  string $enum_nonref_string_path (required)
-     * @param  StringEnumRef $enum_ref_string_path (required)
+     * @param  \OpenAPI\Client\Model\StringEnumRef $enum_ref_string_path (required)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testsPathStringPathStringIntegerPathIntegerEnumNonrefStringPathEnumRefStringPath'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
diff --git a/samples/client/echo_api/php-nextgen/src/Api/QueryApi.php b/samples/client/echo_api/php-nextgen/src/Api/QueryApi.php
index ca420cea4f22..98ab9b319efb 100644
--- a/samples/client/echo_api/php-nextgen/src/Api/QueryApi.php
+++ b/samples/client/echo_api/php-nextgen/src/Api/QueryApi.php
@@ -156,7 +156,7 @@ public function getConfig(): Configuration
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -165,7 +165,7 @@ public function getConfig(): Configuration
      */
     public function testEnumRefString(
         ?string $enum_nonref_string_query = null,
-        ?StringEnumRef $enum_ref_string_query = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_query = null,
         string $contentType = self::contentTypes['testEnumRefString'][0]
     ): string
     {
@@ -179,7 +179,7 @@ public function testEnumRefString(
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -188,7 +188,7 @@ public function testEnumRefString(
      */
     public function testEnumRefStringWithHttpInfo(
         ?string $enum_nonref_string_query = null,
-        ?StringEnumRef $enum_ref_string_query = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_query = null,
         string $contentType = self::contentTypes['testEnumRefString'][0]
     ): array
     {
@@ -308,7 +308,7 @@ public function testEnumRefStringWithHttpInfo(
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -316,7 +316,7 @@ public function testEnumRefStringWithHttpInfo(
      */
     public function testEnumRefStringAsync(
         ?string $enum_nonref_string_query = null,
-        ?StringEnumRef $enum_ref_string_query = null,
+        ?\OpenAPI\Client\Model\StringEnumRef $enum_ref_string_query = null,
         string $contentType = self::contentTypes['testEnumRefString'][0]
     ): PromiseInterface
     {
@@ -334,7 +334,7 @@ function ($response) {
      * Test query parameter(s)
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -389,7 +389,7 @@ function ($exception) {
      * Create request for operation 'testEnumRefString'
      *
      * @param  string|null $enum_nonref_string_query (optional)
-     * @param  StringEnumRef|null $enum_ref_string_query (optional)
+     * @param  \OpenAPI\Client\Model\StringEnumRef|null $enum_ref_string_query (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testEnumRefString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1206,7 +1206,7 @@ public function testQueryIntegerBooleanStringRequest(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1214,7 +1214,7 @@ public function testQueryIntegerBooleanStringRequest(
      * @return string
      */
     public function testQueryStyleDeepObjectExplodeTrueObject(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'][0]
     ): string
     {
@@ -1227,7 +1227,7 @@ public function testQueryStyleDeepObjectExplodeTrueObject(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1235,7 +1235,7 @@ public function testQueryStyleDeepObjectExplodeTrueObject(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectWithHttpInfo(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'][0]
     ): array
     {
@@ -1354,14 +1354,14 @@ public function testQueryStyleDeepObjectExplodeTrueObjectWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAsync(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'][0]
     ): PromiseInterface
     {
@@ -1378,7 +1378,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1431,7 +1431,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleDeepObjectExplodeTrueObject'
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1523,7 +1523,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectRequest(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1531,7 +1531,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectRequest(
      * @return string
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAllOf(
-        ?TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'][0]
     ): string
     {
@@ -1544,7 +1544,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectAllOf(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -1552,7 +1552,7 @@ public function testQueryStyleDeepObjectExplodeTrueObjectAllOf(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAllOfWithHttpInfo(
-        ?TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'][0]
     ): array
     {
@@ -1671,14 +1671,14 @@ public function testQueryStyleDeepObjectExplodeTrueObjectAllOfWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleDeepObjectExplodeTrueObjectAllOfAsync(
-        ?TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'][0]
     ): PromiseInterface
     {
@@ -1695,7 +1695,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -1748,7 +1748,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleDeepObjectExplodeTrueObjectAllOf'
      *
-     * @param  TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleDeepObjectExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -2474,7 +2474,7 @@ public function testQueryStyleFormExplodeFalseArrayStringRequest(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2482,7 +2482,7 @@ public function testQueryStyleFormExplodeFalseArrayStringRequest(
      * @return string
      */
     public function testQueryStyleFormExplodeTrueArrayString(
-        ?TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueArrayString'][0]
     ): string
     {
@@ -2495,7 +2495,7 @@ public function testQueryStyleFormExplodeTrueArrayString(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2503,7 +2503,7 @@ public function testQueryStyleFormExplodeTrueArrayString(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleFormExplodeTrueArrayStringWithHttpInfo(
-        ?TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueArrayString'][0]
     ): array
     {
@@ -2622,14 +2622,14 @@ public function testQueryStyleFormExplodeTrueArrayStringWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleFormExplodeTrueArrayStringAsync(
-        ?TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
+        ?\OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueArrayString'][0]
     ): PromiseInterface
     {
@@ -2646,7 +2646,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -2699,7 +2699,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleFormExplodeTrueArrayString'
      *
-     * @param  TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueArrayString'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -2791,7 +2791,7 @@ public function testQueryStyleFormExplodeTrueArrayStringRequest(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2799,7 +2799,7 @@ public function testQueryStyleFormExplodeTrueArrayStringRequest(
      * @return string
      */
     public function testQueryStyleFormExplodeTrueObject(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObject'][0]
     ): string
     {
@@ -2812,7 +2812,7 @@ public function testQueryStyleFormExplodeTrueObject(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -2820,7 +2820,7 @@ public function testQueryStyleFormExplodeTrueObject(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleFormExplodeTrueObjectWithHttpInfo(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObject'][0]
     ): array
     {
@@ -2939,14 +2939,14 @@ public function testQueryStyleFormExplodeTrueObjectWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleFormExplodeTrueObjectAsync(
-        ?Pet $query_object = null,
+        ?\OpenAPI\Client\Model\Pet $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObject'][0]
     ): PromiseInterface
     {
@@ -2963,7 +2963,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -3016,7 +3016,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleFormExplodeTrueObject'
      *
-     * @param  Pet|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\Pet|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObject'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -3108,7 +3108,7 @@ public function testQueryStyleFormExplodeTrueObjectRequest(
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -3116,7 +3116,7 @@ public function testQueryStyleFormExplodeTrueObjectRequest(
      * @return string
      */
     public function testQueryStyleFormExplodeTrueObjectAllOf(
-        ?DataQuery $query_object = null,
+        ?\OpenAPI\Client\Model\DataQuery $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'][0]
     ): string
     {
@@ -3129,7 +3129,7 @@ public function testQueryStyleFormExplodeTrueObjectAllOf(
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws ApiException on non-2xx response or if the response body is not in the expected format
@@ -3137,7 +3137,7 @@ public function testQueryStyleFormExplodeTrueObjectAllOf(
      * @return array of string, HTTP status code, HTTP response headers (array of strings)
      */
     public function testQueryStyleFormExplodeTrueObjectAllOfWithHttpInfo(
-        ?DataQuery $query_object = null,
+        ?\OpenAPI\Client\Model\DataQuery $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'][0]
     ): array
     {
@@ -3256,14 +3256,14 @@ public function testQueryStyleFormExplodeTrueObjectAllOfWithHttpInfo(
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
      * @return PromiseInterface
      */
     public function testQueryStyleFormExplodeTrueObjectAllOfAsync(
-        ?DataQuery $query_object = null,
+        ?\OpenAPI\Client\Model\DataQuery $query_object = null,
         string $contentType = self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'][0]
     ): PromiseInterface
     {
@@ -3280,7 +3280,7 @@ function ($response) {
      *
      * Test query parameter(s)
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
@@ -3333,7 +3333,7 @@ function ($exception) {
     /**
      * Create request for operation 'testQueryStyleFormExplodeTrueObjectAllOf'
      *
-     * @param  DataQuery|null $query_object (optional)
+     * @param  \OpenAPI\Client\Model\DataQuery|null $query_object (optional)
      * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['testQueryStyleFormExplodeTrueObjectAllOf'] to see the possible values for this operation
      *
      * @throws InvalidArgumentException
diff --git a/samples/client/petstore/php-nextgen/OpenAPIClient-php/README.md b/samples/client/petstore/php-nextgen/OpenAPIClient-php/README.md
index 6b60abeee5f9..f4d8401cd184 100644
--- a/samples/client/petstore/php-nextgen/OpenAPIClient-php/README.md
+++ b/samples/client/petstore/php-nextgen/OpenAPIClient-php/README.md
@@ -74,6 +74,7 @@ Class | Method | HTTP request | Description
 *AnotherFakeApi* | [**call123TestSpecialTags**](docs/Api/AnotherFakeApi.md#call123testspecialtags) | **PATCH** /another-fake/dummy | To test special tags
 *DefaultApi* | [**fooGet**](docs/Api/DefaultApi.md#fooget) | **GET** /foo | 
 *FakeApi* | [**fakeBigDecimalMap**](docs/Api/FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+*FakeApi* | [**fakeEnumEndpoint**](docs/Api/FakeApi.md#fakeenumendpoint) | **GET** /fake/enum/endpoint | test endpoint with enum parameter
 *FakeApi* | [**fakeHealthGet**](docs/Api/FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 *FakeApi* | [**fakeHttpSignatureTest**](docs/Api/FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 *FakeApi* | [**fakeOuterBooleanSerialize**](docs/Api/FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
diff --git a/samples/client/petstore/php-nextgen/OpenAPIClient-php/docs/Api/FakeApi.md b/samples/client/petstore/php-nextgen/OpenAPIClient-php/docs/Api/FakeApi.md
index 39ac3ed2a67b..9f4cab79f2a1 100644
--- a/samples/client/petstore/php-nextgen/OpenAPIClient-php/docs/Api/FakeApi.md
+++ b/samples/client/petstore/php-nextgen/OpenAPIClient-php/docs/Api/FakeApi.md
@@ -5,6 +5,7 @@ All URIs are relative to http://petstore.swagger.io:80/v2, except if the operati
 | Method | HTTP request | Description |
 | ------------- | ------------- | ------------- |
 | [**fakeBigDecimalMap()**](FakeApi.md#fakeBigDecimalMap) | **GET** /fake/BigDecimalMap |  |
+| [**fakeEnumEndpoint()**](FakeApi.md#fakeEnumEndpoint) | **GET** /fake/enum/endpoint | test endpoint with enum parameter |
 | [**fakeHealthGet()**](FakeApi.md#fakeHealthGet) | **GET** /fake/health | Health check endpoint |
 | [**fakeHttpSignatureTest()**](FakeApi.md#fakeHttpSignatureTest) | **GET** /fake/http-signature-test | test http signature authentication |
 | [**fakeOuterBooleanSerialize()**](FakeApi.md#fakeOuterBooleanSerialize) | **POST** /fake/outer/boolean |  |
@@ -81,6 +82,64 @@ No authorization required
 [[Back to Model list]](../../README.md#models)
 [[Back to README]](../../README.md)
 
+## `fakeEnumEndpoint()`
+
+```php
+fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map): \OpenAPI\Client\Model\EnumClass
+```
+
+test endpoint with enum parameter
+
+### Example
+
+```php
+<?php
+require_once(__DIR__ . '/vendor/autoload.php');
+
+
+
+$apiInstance = new OpenAPI\Client\Api\FakeApi(
+    // If you want use custom http client, pass your client which implements `GuzzleHttp\ClientInterface`.
+    // This is optional, `GuzzleHttp\Client` will be used as default.
+    new GuzzleHttp\Client()
+);
+$enum_class = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass(); // \OpenAPI\Client\Model\EnumClass | enum class parameter
+$enum_class_array = array(new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass()); // \OpenAPI\Client\Model\EnumClass[] | enum class parameter
+$enum_class_map = array('key' => new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass()); // array<string,\OpenAPI\Client\Model\EnumClass> | enum class parameter
+
+try {
+    $result = $apiInstance->fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map);
+    print_r($result);
+} catch (Exception $e) {
+    echo 'Exception when calling FakeApi->fakeEnumEndpoint: ', $e->getMessage(), PHP_EOL;
+}
+```
+
+### Parameters
+
+| Name | Type | Description  | Notes |
+| ------------- | ------------- | ------------- | ------------- |
+| **enum_class** | [**\OpenAPI\Client\Model\EnumClass**](../Model/.md)| enum class parameter | |
+| **enum_class_array** | [**\OpenAPI\Client\Model\EnumClass[]**](../Model/\OpenAPI\Client\Model\EnumClass.md)| enum class parameter | |
+| **enum_class_map** | [**array<string,\OpenAPI\Client\Model\EnumClass>**](../Model/\OpenAPI\Client\Model\EnumClass.md)| enum class parameter | |
+
+### Return type
+
+[**\OpenAPI\Client\Model\EnumClass**](../Model/EnumClass.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: `application/json`
+
+[[Back to top]](#) [[Back to API list]](../../README.md#endpoints)
+[[Back to Model list]](../../README.md#models)
+[[Back to README]](../../README.md)
+
 ## `fakeHealthGet()`
 
 ```php
diff --git a/samples/client/petstore/php-nextgen/OpenAPIClient-php/src/Api/FakeApi.php b/samples/client/petstore/php-nextgen/OpenAPIClient-php/src/Api/FakeApi.php
index c44d49f9d4c5..81a7bd290e78 100644
--- a/samples/client/petstore/php-nextgen/OpenAPIClient-php/src/Api/FakeApi.php
+++ b/samples/client/petstore/php-nextgen/OpenAPIClient-php/src/Api/FakeApi.php
@@ -74,6 +74,9 @@ class FakeApi
         'fakeBigDecimalMap' => [
             'application/json',
         ],
+        'fakeEnumEndpoint' => [
+            'application/json',
+        ],
         'fakeHealthGet' => [
             'application/json',
         ],
@@ -475,6 +478,381 @@ public function fakeBigDecimalMapRequest(
         );
     }
 
+    /**
+     * Operation fakeEnumEndpoint
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws ApiException on non-2xx response or if the response body is not in the expected format
+     * @throws InvalidArgumentException
+     * @return \OpenAPI\Client\Model\EnumClass
+     */
+    public function fakeEnumEndpoint(
+        \OpenAPI\Client\Model\EnumClass $enum_class,
+        array $enum_class_array,
+        array $enum_class_map,
+        string $contentType = self::contentTypes['fakeEnumEndpoint'][0]
+    ): \OpenAPI\Client\Model\EnumClass
+    {
+        list($response) = $this->fakeEnumEndpointWithHttpInfo($enum_class, $enum_class_array, $enum_class_map, $contentType);
+        return $response;
+    }
+
+    /**
+     * Operation fakeEnumEndpointWithHttpInfo
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws ApiException on non-2xx response or if the response body is not in the expected format
+     * @throws InvalidArgumentException
+     * @return array of \OpenAPI\Client\Model\EnumClass, HTTP status code, HTTP response headers (array of strings)
+     */
+    public function fakeEnumEndpointWithHttpInfo(
+        \OpenAPI\Client\Model\EnumClass $enum_class,
+        array $enum_class_array,
+        array $enum_class_map,
+        string $contentType = self::contentTypes['fakeEnumEndpoint'][0]
+    ): array
+    {
+        $request = $this->fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map, $contentType);
+
+        try {
+            $options = $this->createHttpClientOption();
+            try {
+                $response = $this->client->send($request, $options);
+            } catch (RequestException $e) {
+                throw new ApiException(
+                    "[{$e->getCode()}] {$e->getMessage()}",
+                    (int) $e->getCode(),
+                    $e->getResponse() ? $e->getResponse()->getHeaders() : null,
+                    $e->getResponse() ? (string) $e->getResponse()->getBody() : null
+                );
+            } catch (ConnectException $e) {
+                throw new ApiException(
+                    "[{$e->getCode()}] {$e->getMessage()}",
+                    (int) $e->getCode(),
+                    null,
+                    null
+                );
+            }
+
+            $statusCode = $response->getStatusCode();
+
+            if ($statusCode < 200 || $statusCode > 299) {
+                throw new ApiException(
+                    sprintf(
+                        '[%d] Error connecting to the API (%s)',
+                        $statusCode,
+                        (string) $request->getUri()
+                    ),
+                    $statusCode,
+                    $response->getHeaders(),
+                    (string) $response->getBody()
+                );
+            }
+
+            switch($statusCode) {
+                case 200:
+                    if (in_array('\OpenAPI\Client\Model\EnumClass', ['\SplFileObject', '\Psr\Http\Message\StreamInterface'])) {
+                        $content = $response->getBody(); //stream goes to serializer
+                    } else {
+                        $content = (string) $response->getBody();
+                        if ('\OpenAPI\Client\Model\EnumClass' !== 'string') {
+                            try {
+                                $content = json_decode($content, false, 512, JSON_THROW_ON_ERROR);
+                            } catch (\JsonException $exception) {
+                                throw new ApiException(
+                                    sprintf(
+                                        'Error JSON decoding server response (%s)',
+                                        $request->getUri()
+                                    ),
+                                    $statusCode,
+                                    $response->getHeaders(),
+                                    $content
+                                );
+                            }
+                        }
+                    }
+
+                    return [
+                        ObjectSerializer::deserialize($content, '\OpenAPI\Client\Model\EnumClass', []),
+                        $response->getStatusCode(),
+                        $response->getHeaders()
+                    ];
+            }
+
+            $returnType = '\OpenAPI\Client\Model\EnumClass';
+            if (in_array($returnType, ['\SplFileObject', '\Psr\Http\Message\StreamInterface'])) {
+                $content = $response->getBody(); //stream goes to serializer
+            } else {
+                $content = (string) $response->getBody();
+                if ($returnType !== 'string') {
+                    try {
+                        $content = json_decode($content, false, 512, JSON_THROW_ON_ERROR);
+                    } catch (\JsonException $exception) {
+                        throw new ApiException(
+                            sprintf(
+                                'Error JSON decoding server response (%s)',
+                                $request->getUri()
+                            ),
+                            $statusCode,
+                            $response->getHeaders(),
+                            $content
+                        );
+                    }
+                }
+            }
+
+            return [
+                ObjectSerializer::deserialize($content, $returnType, []),
+                $response->getStatusCode(),
+                $response->getHeaders()
+            ];
+
+        } catch (ApiException $e) {
+            switch ($e->getCode()) {
+                case 200:
+                    $data = ObjectSerializer::deserialize(
+                        $e->getResponseBody(),
+                        '\OpenAPI\Client\Model\EnumClass',
+                        $e->getResponseHeaders()
+                    );
+                    $e->setResponseObject($data);
+                    break;
+            }
+            throw $e;
+        }
+    }
+
+    /**
+     * Operation fakeEnumEndpointAsync
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws InvalidArgumentException
+     * @return PromiseInterface
+     */
+    public function fakeEnumEndpointAsync(
+        \OpenAPI\Client\Model\EnumClass $enum_class,
+        array $enum_class_array,
+        array $enum_class_map,
+        string $contentType = self::contentTypes['fakeEnumEndpoint'][0]
+    ): PromiseInterface
+    {
+        return $this->fakeEnumEndpointAsyncWithHttpInfo($enum_class, $enum_class_array, $enum_class_map, $contentType)
+            ->then(
+                function ($response) {
+                    return $response[0];
+                }
+            );
+    }
+
+    /**
+     * Operation fakeEnumEndpointAsyncWithHttpInfo
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws InvalidArgumentException
+     * @return PromiseInterface
+     */
+    public function fakeEnumEndpointAsyncWithHttpInfo(
+        $enum_class,
+        $enum_class_array,
+        $enum_class_map,
+        string $contentType = self::contentTypes['fakeEnumEndpoint'][0]
+    ): PromiseInterface
+    {
+        $returnType = '\OpenAPI\Client\Model\EnumClass';
+        $request = $this->fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map, $contentType);
+
+        return $this->client
+            ->sendAsync($request, $this->createHttpClientOption())
+            ->then(
+                function ($response) use ($returnType) {
+                    if (in_array($returnType, ['\SplFileObject', '\Psr\Http\Message\StreamInterface'])) {
+                        $content = $response->getBody(); //stream goes to serializer
+                    } else {
+                        $content = (string) $response->getBody();
+                        if ($returnType !== 'string') {
+                            $content = json_decode($content);
+                        }
+                    }
+
+                    return [
+                        ObjectSerializer::deserialize($content, $returnType, []),
+                        $response->getStatusCode(),
+                        $response->getHeaders()
+                    ];
+                },
+                function ($exception) {
+                    $response = $exception->getResponse();
+                    $statusCode = $response->getStatusCode();
+                    throw new ApiException(
+                        sprintf(
+                            '[%d] Error connecting to the API (%s)',
+                            $statusCode,
+                            $exception->getRequest()->getUri()
+                        ),
+                        $statusCode,
+                        $response->getHeaders(),
+                        (string) $response->getBody()
+                    );
+                }
+            );
+    }
+
+    /**
+     * Create request for operation 'fakeEnumEndpoint'
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws InvalidArgumentException
+     * @return \GuzzleHttp\Psr7\Request
+     */
+    public function fakeEnumEndpointRequest(
+        $enum_class,
+        $enum_class_array,
+        $enum_class_map,
+        string $contentType = self::contentTypes['fakeEnumEndpoint'][0]
+    ): Request
+    {
+
+        // verify the required parameter 'enum_class' is set
+        if ($enum_class === null || (is_array($enum_class) && count($enum_class) === 0)) {
+            throw new InvalidArgumentException(
+                'Missing the required parameter $enum_class when calling fakeEnumEndpoint'
+            );
+        }
+
+        // verify the required parameter 'enum_class_array' is set
+        if ($enum_class_array === null || (is_array($enum_class_array) && count($enum_class_array) === 0)) {
+            throw new InvalidArgumentException(
+                'Missing the required parameter $enum_class_array when calling fakeEnumEndpoint'
+            );
+        }
+
+        // verify the required parameter 'enum_class_map' is set
+        if ($enum_class_map === null || (is_array($enum_class_map) && count($enum_class_map) === 0)) {
+            throw new InvalidArgumentException(
+                'Missing the required parameter $enum_class_map when calling fakeEnumEndpoint'
+            );
+        }
+
+
+        $resourcePath = '/fake/enum/endpoint';
+        $formParams = [];
+        $queryParams = [];
+        $headerParams = [];
+        $httpBody = '';
+        $multipart = false;
+
+        // query params
+        $queryParams = array_merge($queryParams, ObjectSerializer::toQueryValue(
+            $enum_class,
+            'enum-class', // param base name
+            'EnumClass', // openApiType
+            'form', // style
+            true, // explode
+            true // required
+        ) ?? []);
+        // query params
+        $queryParams = array_merge($queryParams, ObjectSerializer::toQueryValue(
+            $enum_class_array,
+            'enum-class-array', // param base name
+            'array', // openApiType
+            'form', // style
+            true, // explode
+            true // required
+        ) ?? []);
+        // query params
+        $queryParams = array_merge($queryParams, ObjectSerializer::toQueryValue(
+            $enum_class_map,
+            'enum-class-map', // param base name
+            'object', // openApiType
+            'form', // style
+            true, // explode
+            true // required
+        ) ?? []);
+
+
+
+
+        $headers = $this->headerSelector->selectHeaders(
+            ['application/json', ],
+            $contentType,
+            $multipart
+        );
+
+        // for model (json/xml)
+        if (count($formParams) > 0) {
+            if ($multipart) {
+                $multipartContents = [];
+                foreach ($formParams as $formParamName => $formParamValue) {
+                    $formParamValueItems = is_array($formParamValue) ? $formParamValue : [$formParamValue];
+                    foreach ($formParamValueItems as $formParamValueItem) {
+                        $multipartContents[] = [
+                            'name' => $formParamName,
+                            'contents' => $formParamValueItem
+                        ];
+                    }
+                }
+                // for HTTP post (form)
+                $httpBody = new MultipartStream($multipartContents);
+
+            } elseif (stripos($headers['Content-Type'], 'application/json') !== false) {
+                # if Content-Type contains "application/json", json_encode the form parameters
+                $httpBody = \GuzzleHttp\Utils::jsonEncode($formParams);
+            } else {
+                // for HTTP post (form)
+                $httpBody = ObjectSerializer::buildQuery($formParams);
+            }
+        }
+
+
+        $defaultHeaders = [];
+        if ($this->config->getUserAgent()) {
+            $defaultHeaders['User-Agent'] = $this->config->getUserAgent();
+        }
+
+        $headers = array_merge(
+            $defaultHeaders,
+            $headerParams,
+            $headers
+        );
+
+        $operationHost = $this->config->getHost();
+        $query = ObjectSerializer::buildQuery($queryParams);
+        return new Request(
+            'GET',
+            $operationHost . $resourcePath . ($query ? "?{$query}" : ''),
+            $headers,
+            $httpBody
+        );
+    }
+
     /**
      * Operation fakeHealthGet
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/README.md b/samples/client/petstore/php/OpenAPIClient-php/README.md
index 175b40d839f1..aaad207f4abb 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/README.md
+++ b/samples/client/petstore/php/OpenAPIClient-php/README.md
@@ -75,6 +75,7 @@ Class | Method | HTTP request | Description
 *AnotherFakeApi* | [**call123TestSpecialTags**](docs/Api/AnotherFakeApi.md#call123testspecialtags) | **PATCH** /another-fake/dummy | To test special tags
 *DefaultApi* | [**fooGet**](docs/Api/DefaultApi.md#fooget) | **GET** /foo | 
 *FakeApi* | [**fakeBigDecimalMap**](docs/Api/FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+*FakeApi* | [**fakeEnumEndpoint**](docs/Api/FakeApi.md#fakeenumendpoint) | **GET** /fake/enum/endpoint | test endpoint with enum parameter
 *FakeApi* | [**fakeHealthGet**](docs/Api/FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 *FakeApi* | [**fakeHttpSignatureTest**](docs/Api/FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 *FakeApi* | [**fakeOuterBooleanSerialize**](docs/Api/FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
diff --git a/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md b/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
index 92da9fdf9929..87e2653832dc 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
+++ b/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
@@ -5,6 +5,7 @@ All URIs are relative to http://petstore.swagger.io:80/v2, except if the operati
 | Method | HTTP request | Description |
 | ------------- | ------------- | ------------- |
 | [**fakeBigDecimalMap()**](FakeApi.md#fakeBigDecimalMap) | **GET** /fake/BigDecimalMap |  |
+| [**fakeEnumEndpoint()**](FakeApi.md#fakeEnumEndpoint) | **GET** /fake/enum/endpoint | test endpoint with enum parameter |
 | [**fakeHealthGet()**](FakeApi.md#fakeHealthGet) | **GET** /fake/health | Health check endpoint |
 | [**fakeHttpSignatureTest()**](FakeApi.md#fakeHttpSignatureTest) | **GET** /fake/http-signature-test | test http signature authentication |
 | [**fakeOuterBooleanSerialize()**](FakeApi.md#fakeOuterBooleanSerialize) | **POST** /fake/outer/boolean |  |
@@ -81,6 +82,64 @@ No authorization required
 [[Back to Model list]](../../README.md#models)
 [[Back to README]](../../README.md)
 
+## `fakeEnumEndpoint()`
+
+```php
+fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map): \OpenAPI\Client\Model\EnumClass
+```
+
+test endpoint with enum parameter
+
+### Example
+
+```php
+<?php
+require_once(__DIR__ . '/vendor/autoload.php');
+
+
+
+$apiInstance = new OpenAPI\Client\Api\FakeApi(
+    // If you want use custom http client, pass your client which implements `GuzzleHttp\ClientInterface`.
+    // This is optional, `GuzzleHttp\Client` will be used as default.
+    new GuzzleHttp\Client()
+);
+$enum_class = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass(); // \OpenAPI\Client\Model\EnumClass | enum class parameter
+$enum_class_array = array(new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass()); // \OpenAPI\Client\Model\EnumClass[] | enum class parameter
+$enum_class_map = array('key' => new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass()); // array<string,\OpenAPI\Client\Model\EnumClass> | enum class parameter
+
+try {
+    $result = $apiInstance->fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map);
+    print_r($result);
+} catch (Exception $e) {
+    echo 'Exception when calling FakeApi->fakeEnumEndpoint: ', $e->getMessage(), PHP_EOL;
+}
+```
+
+### Parameters
+
+| Name | Type | Description  | Notes |
+| ------------- | ------------- | ------------- | ------------- |
+| **enum_class** | [**\OpenAPI\Client\Model\EnumClass**](../Model/.md)| enum class parameter | |
+| **enum_class_array** | [**\OpenAPI\Client\Model\EnumClass[]**](../Model/\OpenAPI\Client\Model\EnumClass.md)| enum class parameter | |
+| **enum_class_map** | [**array<string,\OpenAPI\Client\Model\EnumClass>**](../Model/\OpenAPI\Client\Model\EnumClass.md)| enum class parameter | |
+
+### Return type
+
+[**\OpenAPI\Client\Model\EnumClass**](../Model/EnumClass.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: `application/json`
+
+[[Back to top]](#) [[Back to API list]](../../README.md#endpoints)
+[[Back to Model list]](../../README.md#models)
+[[Back to README]](../../README.md)
+
 ## `fakeHealthGet()`
 
 ```php
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
index c39f19e0fc70..81dac54f386c 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
@@ -74,6 +74,9 @@ class FakeApi
         'fakeBigDecimalMap' => [
             'application/json',
         ],
+        'fakeEnumEndpoint' => [
+            'application/json',
+        ],
         'fakeHealthGet' => [
             'application/json',
         ],
@@ -465,6 +468,356 @@ public function fakeBigDecimalMapRequest(string $contentType = self::contentType
         );
     }
 
+    /**
+     * Operation fakeEnumEndpoint
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws \OpenAPI\Client\ApiException on non-2xx response or if the response body is not in the expected format
+     * @throws \InvalidArgumentException
+     * @return \OpenAPI\Client\Model\EnumClass
+     */
+    public function fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map, string $contentType = self::contentTypes['fakeEnumEndpoint'][0])
+    {
+        list($response) = $this->fakeEnumEndpointWithHttpInfo($enum_class, $enum_class_array, $enum_class_map, $contentType);
+        return $response;
+    }
+
+    /**
+     * Operation fakeEnumEndpointWithHttpInfo
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws \OpenAPI\Client\ApiException on non-2xx response or if the response body is not in the expected format
+     * @throws \InvalidArgumentException
+     * @return array of \OpenAPI\Client\Model\EnumClass, HTTP status code, HTTP response headers (array of strings)
+     */
+    public function fakeEnumEndpointWithHttpInfo($enum_class, $enum_class_array, $enum_class_map, string $contentType = self::contentTypes['fakeEnumEndpoint'][0])
+    {
+        $request = $this->fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map, $contentType);
+
+        try {
+            $options = $this->createHttpClientOption();
+            try {
+                $response = $this->client->send($request, $options);
+            } catch (RequestException $e) {
+                throw new ApiException(
+                    "[{$e->getCode()}] {$e->getMessage()}",
+                    (int) $e->getCode(),
+                    $e->getResponse() ? $e->getResponse()->getHeaders() : null,
+                    $e->getResponse() ? (string) $e->getResponse()->getBody() : null
+                );
+            } catch (ConnectException $e) {
+                throw new ApiException(
+                    "[{$e->getCode()}] {$e->getMessage()}",
+                    (int) $e->getCode(),
+                    null,
+                    null
+                );
+            }
+
+            $statusCode = $response->getStatusCode();
+
+            if ($statusCode < 200 || $statusCode > 299) {
+                throw new ApiException(
+                    sprintf(
+                        '[%d] Error connecting to the API (%s)',
+                        $statusCode,
+                        (string) $request->getUri()
+                    ),
+                    $statusCode,
+                    $response->getHeaders(),
+                    (string) $response->getBody()
+                );
+            }
+
+            switch($statusCode) {
+                case 200:
+                    if ('\OpenAPI\Client\Model\EnumClass' === '\SplFileObject') {
+                        $content = $response->getBody(); //stream goes to serializer
+                    } else {
+                        $content = (string) $response->getBody();
+                        if ('\OpenAPI\Client\Model\EnumClass' !== 'string') {
+                            try {
+                                $content = json_decode($content, false, 512, JSON_THROW_ON_ERROR);
+                            } catch (\JsonException $exception) {
+                                throw new ApiException(
+                                    sprintf(
+                                        'Error JSON decoding server response (%s)',
+                                        $request->getUri()
+                                    ),
+                                    $statusCode,
+                                    $response->getHeaders(),
+                                    $content
+                                );
+                            }
+                        }
+                    }
+
+                    return [
+                        ObjectSerializer::deserialize($content, '\OpenAPI\Client\Model\EnumClass', []),
+                        $response->getStatusCode(),
+                        $response->getHeaders()
+                    ];
+            }
+
+            $returnType = '\OpenAPI\Client\Model\EnumClass';
+            if ($returnType === '\SplFileObject') {
+                $content = $response->getBody(); //stream goes to serializer
+            } else {
+                $content = (string) $response->getBody();
+                if ($returnType !== 'string') {
+                    try {
+                        $content = json_decode($content, false, 512, JSON_THROW_ON_ERROR);
+                    } catch (\JsonException $exception) {
+                        throw new ApiException(
+                            sprintf(
+                                'Error JSON decoding server response (%s)',
+                                $request->getUri()
+                            ),
+                            $statusCode,
+                            $response->getHeaders(),
+                            $content
+                        );
+                    }
+                }
+            }
+
+            return [
+                ObjectSerializer::deserialize($content, $returnType, []),
+                $response->getStatusCode(),
+                $response->getHeaders()
+            ];
+
+        } catch (ApiException $e) {
+            switch ($e->getCode()) {
+                case 200:
+                    $data = ObjectSerializer::deserialize(
+                        $e->getResponseBody(),
+                        '\OpenAPI\Client\Model\EnumClass',
+                        $e->getResponseHeaders()
+                    );
+                    $e->setResponseObject($data);
+                    break;
+            }
+            throw $e;
+        }
+    }
+
+    /**
+     * Operation fakeEnumEndpointAsync
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws \InvalidArgumentException
+     * @return \GuzzleHttp\Promise\PromiseInterface
+     */
+    public function fakeEnumEndpointAsync($enum_class, $enum_class_array, $enum_class_map, string $contentType = self::contentTypes['fakeEnumEndpoint'][0])
+    {
+        return $this->fakeEnumEndpointAsyncWithHttpInfo($enum_class, $enum_class_array, $enum_class_map, $contentType)
+            ->then(
+                function ($response) {
+                    return $response[0];
+                }
+            );
+    }
+
+    /**
+     * Operation fakeEnumEndpointAsyncWithHttpInfo
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws \InvalidArgumentException
+     * @return \GuzzleHttp\Promise\PromiseInterface
+     */
+    public function fakeEnumEndpointAsyncWithHttpInfo($enum_class, $enum_class_array, $enum_class_map, string $contentType = self::contentTypes['fakeEnumEndpoint'][0])
+    {
+        $returnType = '\OpenAPI\Client\Model\EnumClass';
+        $request = $this->fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map, $contentType);
+
+        return $this->client
+            ->sendAsync($request, $this->createHttpClientOption())
+            ->then(
+                function ($response) use ($returnType) {
+                    if ($returnType === '\SplFileObject') {
+                        $content = $response->getBody(); //stream goes to serializer
+                    } else {
+                        $content = (string) $response->getBody();
+                        if ($returnType !== 'string') {
+                            $content = json_decode($content);
+                        }
+                    }
+
+                    return [
+                        ObjectSerializer::deserialize($content, $returnType, []),
+                        $response->getStatusCode(),
+                        $response->getHeaders()
+                    ];
+                },
+                function ($exception) {
+                    $response = $exception->getResponse();
+                    $statusCode = $response->getStatusCode();
+                    throw new ApiException(
+                        sprintf(
+                            '[%d] Error connecting to the API (%s)',
+                            $statusCode,
+                            $exception->getRequest()->getUri()
+                        ),
+                        $statusCode,
+                        $response->getHeaders(),
+                        (string) $response->getBody()
+                    );
+                }
+            );
+    }
+
+    /**
+     * Create request for operation 'fakeEnumEndpoint'
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     * @param  string $contentType The value for the Content-Type header. Check self::contentTypes['fakeEnumEndpoint'] to see the possible values for this operation
+     *
+     * @throws \InvalidArgumentException
+     * @return \GuzzleHttp\Psr7\Request
+     */
+    public function fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map, string $contentType = self::contentTypes['fakeEnumEndpoint'][0])
+    {
+
+        // verify the required parameter 'enum_class' is set
+        if ($enum_class === null || (is_array($enum_class) && count($enum_class) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $enum_class when calling fakeEnumEndpoint'
+            );
+        }
+
+        // verify the required parameter 'enum_class_array' is set
+        if ($enum_class_array === null || (is_array($enum_class_array) && count($enum_class_array) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $enum_class_array when calling fakeEnumEndpoint'
+            );
+        }
+
+        // verify the required parameter 'enum_class_map' is set
+        if ($enum_class_map === null || (is_array($enum_class_map) && count($enum_class_map) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $enum_class_map when calling fakeEnumEndpoint'
+            );
+        }
+
+
+        $resourcePath = '/fake/enum/endpoint';
+        $formParams = [];
+        $queryParams = [];
+        $headerParams = [];
+        $httpBody = '';
+        $multipart = false;
+
+        // query params
+        $queryParams = array_merge($queryParams, ObjectSerializer::toQueryValue(
+            $enum_class,
+            'enum-class', // param base name
+            'EnumClass', // openApiType
+            'form', // style
+            true, // explode
+            true // required
+        ) ?? []);
+        // query params
+        $queryParams = array_merge($queryParams, ObjectSerializer::toQueryValue(
+            $enum_class_array,
+            'enum-class-array', // param base name
+            'array', // openApiType
+            'form', // style
+            true, // explode
+            true // required
+        ) ?? []);
+        // query params
+        $queryParams = array_merge($queryParams, ObjectSerializer::toQueryValue(
+            $enum_class_map,
+            'enum-class-map', // param base name
+            'object', // openApiType
+            'form', // style
+            true, // explode
+            true // required
+        ) ?? []);
+
+
+
+
+        $headers = $this->headerSelector->selectHeaders(
+            ['application/json', ],
+            $contentType,
+            $multipart
+        );
+
+        // for model (json/xml)
+        if (count($formParams) > 0) {
+            if ($multipart) {
+                $multipartContents = [];
+                foreach ($formParams as $formParamName => $formParamValue) {
+                    $formParamValueItems = is_array($formParamValue) ? $formParamValue : [$formParamValue];
+                    foreach ($formParamValueItems as $formParamValueItem) {
+                        $multipartContents[] = [
+                            'name' => $formParamName,
+                            'contents' => $formParamValueItem
+                        ];
+                    }
+                }
+                // for HTTP post (form)
+                $httpBody = new MultipartStream($multipartContents);
+
+            } elseif (stripos($headers['Content-Type'], 'application/json') !== false) {
+                # if Content-Type contains "application/json", json_encode the form parameters
+                $httpBody = \GuzzleHttp\Utils::jsonEncode($formParams);
+            } else {
+                // for HTTP post (form)
+                $httpBody = ObjectSerializer::buildQuery($formParams);
+            }
+        }
+
+
+        $defaultHeaders = [];
+        if ($this->config->getUserAgent()) {
+            $defaultHeaders['User-Agent'] = $this->config->getUserAgent();
+        }
+
+        $headers = array_merge(
+            $defaultHeaders,
+            $headerParams,
+            $headers
+        );
+
+        $operationHost = $this->config->getHost();
+        $query = ObjectSerializer::buildQuery($queryParams);
+        return new Request(
+            'GET',
+            $operationHost . $resourcePath . ($query ? "?{$query}" : ''),
+            $headers,
+            $httpBody
+        );
+    }
+
     /**
      * Operation fakeHealthGet
      *
diff --git a/samples/client/petstore/php/psr-18/README.md b/samples/client/petstore/php/psr-18/README.md
index 001ba90f9477..6ab2977051d8 100644
--- a/samples/client/petstore/php/psr-18/README.md
+++ b/samples/client/petstore/php/psr-18/README.md
@@ -86,6 +86,7 @@ Class | Method | HTTP request | Description
 *AnotherFakeApi* | [**call123TestSpecialTags**](docs/Api/AnotherFakeApi.md#call123testspecialtags) | **PATCH** /another-fake/dummy | To test special tags
 *DefaultApi* | [**fooGet**](docs/Api/DefaultApi.md#fooget) | **GET** /foo | 
 *FakeApi* | [**fakeBigDecimalMap**](docs/Api/FakeApi.md#fakebigdecimalmap) | **GET** /fake/BigDecimalMap | 
+*FakeApi* | [**fakeEnumEndpoint**](docs/Api/FakeApi.md#fakeenumendpoint) | **GET** /fake/enum/endpoint | test endpoint with enum parameter
 *FakeApi* | [**fakeHealthGet**](docs/Api/FakeApi.md#fakehealthget) | **GET** /fake/health | Health check endpoint
 *FakeApi* | [**fakeHttpSignatureTest**](docs/Api/FakeApi.md#fakehttpsignaturetest) | **GET** /fake/http-signature-test | test http signature authentication
 *FakeApi* | [**fakeOuterBooleanSerialize**](docs/Api/FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
diff --git a/samples/client/petstore/php/psr-18/docs/Api/FakeApi.md b/samples/client/petstore/php/psr-18/docs/Api/FakeApi.md
index 8b2abf751607..a63a2afacf0e 100644
--- a/samples/client/petstore/php/psr-18/docs/Api/FakeApi.md
+++ b/samples/client/petstore/php/psr-18/docs/Api/FakeApi.md
@@ -5,6 +5,7 @@ All URIs are relative to http://petstore.swagger.io:80/v2.
 Method | HTTP request | Description
 ------------- | ------------- | -------------
 [**fakeBigDecimalMap()**](FakeApi.md#fakeBigDecimalMap) | **GET** /fake/BigDecimalMap | 
+[**fakeEnumEndpoint()**](FakeApi.md#fakeEnumEndpoint) | **GET** /fake/enum/endpoint | test endpoint with enum parameter
 [**fakeHealthGet()**](FakeApi.md#fakeHealthGet) | **GET** /fake/health | Health check endpoint
 [**fakeHttpSignatureTest()**](FakeApi.md#fakeHttpSignatureTest) | **GET** /fake/http-signature-test | test http signature authentication
 [**fakeOuterBooleanSerialize()**](FakeApi.md#fakeOuterBooleanSerialize) | **POST** /fake/outer/boolean | 
@@ -81,6 +82,64 @@ No authorization required
 [[Back to Model list]](../../README.md#models)
 [[Back to README]](../../README.md)
 
+## `fakeEnumEndpoint()`
+
+```php
+fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map): \OpenAPI\Client\Model\EnumClass
+```
+
+test endpoint with enum parameter
+
+### Example
+
+```php
+<?php
+require_once(__DIR__ . '/vendor/autoload.php');
+
+
+
+$apiInstance = new OpenAPI\Client\Api\FakeApi(
+    // If you want use custom http client, pass your client which implements `Psr\Http\Client\ClientInterface`.
+    // This is optional, `Psr18ClientDiscovery` will be used to find http client. For instance `GuzzleHttp\Client` implements that interface
+    new GuzzleHttp\Client()
+);
+$enum_class = new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass(); // \OpenAPI\Client\Model\EnumClass | enum class parameter
+$enum_class_array = array(new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass()); // \OpenAPI\Client\Model\EnumClass[] | enum class parameter
+$enum_class_map = array('key' => new \OpenAPI\Client\Model\\OpenAPI\Client\Model\EnumClass()); // array<string,\OpenAPI\Client\Model\EnumClass> | enum class parameter
+
+try {
+    $result = $apiInstance->fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map);
+    print_r($result);
+} catch (Exception $e) {
+    echo 'Exception when calling FakeApi->fakeEnumEndpoint: ', $e->getMessage(), PHP_EOL;
+}
+```
+
+### Parameters
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **enum_class** | [**\OpenAPI\Client\Model\EnumClass**](../Model/.md)| enum class parameter |
+ **enum_class_array** | [**\OpenAPI\Client\Model\EnumClass[]**](../Model/\OpenAPI\Client\Model\EnumClass.md)| enum class parameter |
+ **enum_class_map** | [**array<string,\OpenAPI\Client\Model\EnumClass>**](../Model/\OpenAPI\Client\Model\EnumClass.md)| enum class parameter |
+
+### Return type
+
+[**\OpenAPI\Client\Model\EnumClass**](../Model/EnumClass.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: Not defined
+- **Accept**: `application/json`
+
+[[Back to top]](#) [[Back to API list]](../../README.md#endpoints)
+[[Back to Model list]](../../README.md#models)
+[[Back to README]](../../README.md)
+
 ## `fakeHealthGet()`
 
 ```php
diff --git a/samples/client/petstore/php/psr-18/lib/Api/FakeApi.php b/samples/client/petstore/php/psr-18/lib/Api/FakeApi.php
index a868ced9cf54..2fb98109e5bf 100644
--- a/samples/client/petstore/php/psr-18/lib/Api/FakeApi.php
+++ b/samples/client/petstore/php/psr-18/lib/Api/FakeApi.php
@@ -399,6 +399,307 @@ public function fakeBigDecimalMapRequest()
         return $this->createRequest('GET', $uri, $headers, $httpBody);
     }
 
+    /**
+     * Operation fakeEnumEndpoint
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     *
+     * @throws \OpenAPI\Client\ApiException on non-2xx response
+     * @throws \InvalidArgumentException
+     * @return \OpenAPI\Client\Model\EnumClass
+     */
+    public function fakeEnumEndpoint($enum_class, $enum_class_array, $enum_class_map)
+    {
+        list($response) = $this->fakeEnumEndpointWithHttpInfo($enum_class, $enum_class_array, $enum_class_map);
+        return $response;
+    }
+
+    /**
+     * Operation fakeEnumEndpointWithHttpInfo
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     *
+     * @throws \OpenAPI\Client\ApiException on non-2xx response
+     * @throws \InvalidArgumentException
+     * @return array of \OpenAPI\Client\Model\EnumClass, HTTP status code, HTTP response headers (array of strings)
+     */
+    public function fakeEnumEndpointWithHttpInfo($enum_class, $enum_class_array, $enum_class_map)
+    {
+        $request = $this->fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map);
+
+        try {
+            try {
+                $response = $this->httpClient->sendRequest($request);
+            } catch (HttpException $e) {
+                $response = $e->getResponse();
+                throw new ApiException(
+                    sprintf(
+                        '[%d] Error connecting to the API (%s)',
+                        $response->getStatusCode(),
+                        (string) $request->getUri()
+                    ),
+                    $request,
+                    $response,
+                    $e
+                );
+            } catch (ClientExceptionInterface $e) {
+                throw new ApiException(
+                    "[{$e->getCode()}] {$e->getMessage()}",
+                    $request,
+                    null,
+                    $e
+                );
+            }
+
+            $statusCode = $response->getStatusCode();
+
+            switch($statusCode) {
+                case 200:
+                    if ('\OpenAPI\Client\Model\EnumClass' === '\SplFileObject') {
+                        $content = $response->getBody(); //stream goes to serializer
+                    } else {
+                        $content = (string) $response->getBody();
+                    }
+
+                    return [
+                        ObjectSerializer::deserialize($content, '\OpenAPI\Client\Model\EnumClass', []),
+                        $response->getStatusCode(),
+                        $response->getHeaders()
+                    ];
+            }
+
+            $returnType = '\OpenAPI\Client\Model\EnumClass';
+            if ($returnType === '\SplFileObject') {
+                $content = $response->getBody(); //stream goes to serializer
+            } else {
+                $content = (string) $response->getBody();
+            }
+
+            return [
+                ObjectSerializer::deserialize($content, $returnType, []),
+                $response->getStatusCode(),
+                $response->getHeaders()
+            ];
+
+        } catch (ApiException $e) {
+            switch ($e->getCode()) {
+                case 200:
+                    $data = ObjectSerializer::deserialize(
+                        $e->getResponseBody(),
+                        '\OpenAPI\Client\Model\EnumClass',
+                        $e->getResponseHeaders()
+                    );
+                    $e->setResponseObject($data);
+                    break;
+            }
+            throw $e;
+        }
+    }
+
+    /**
+     * Operation fakeEnumEndpointAsync
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     *
+     * @throws \InvalidArgumentException
+     * @return Promise
+     */
+    public function fakeEnumEndpointAsync($enum_class, $enum_class_array, $enum_class_map)
+    {
+        return $this->fakeEnumEndpointAsyncWithHttpInfo($enum_class, $enum_class_array, $enum_class_map)
+            ->then(
+                function ($response) {
+                    return $response[0];
+                }
+            );
+    }
+
+    /**
+     * Operation fakeEnumEndpointAsyncWithHttpInfo
+     *
+     * test endpoint with enum parameter
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     *
+     * @throws \InvalidArgumentException
+     * @return Promise
+     */
+    public function fakeEnumEndpointAsyncWithHttpInfo($enum_class, $enum_class_array, $enum_class_map)
+    {
+        $returnType = '\OpenAPI\Client\Model\EnumClass';
+        $request = $this->fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map);
+
+        return $this->httpAsyncClient->sendAsyncRequest($request)
+            ->then(
+                function ($response) use ($returnType) {
+                    if ($returnType === '\SplFileObject') {
+                        $content = $response->getBody(); //stream goes to serializer
+                    } else {
+                        $content = (string) $response->getBody();
+                    }
+
+                    return [
+                        ObjectSerializer::deserialize($content, $returnType, []),
+                        $response->getStatusCode(),
+                        $response->getHeaders()
+                    ];
+                },
+                function (HttpException $exception) {
+                    $response = $exception->getResponse();
+                    $statusCode = $response->getStatusCode();
+                    throw new ApiException(
+                        sprintf(
+                            '[%d] Error connecting to the API (%s)',
+                            $statusCode,
+                            $exception->getRequest()->getUri()
+                        ),
+                        $exception->getRequest(),
+                        $exception->getResponse(),
+                        $exception
+                    );
+                }
+            );
+    }
+
+    /**
+     * Create request for operation 'fakeEnumEndpoint'
+     *
+     * @param  \OpenAPI\Client\Model\EnumClass $enum_class enum class parameter (required)
+     * @param  \OpenAPI\Client\Model\EnumClass[] $enum_class_array enum class parameter (required)
+     * @param  array<string,\OpenAPI\Client\Model\EnumClass> $enum_class_map enum class parameter (required)
+     *
+     * @throws \InvalidArgumentException
+     * @return RequestInterface
+     */
+    public function fakeEnumEndpointRequest($enum_class, $enum_class_array, $enum_class_map)
+    {
+        // verify the required parameter 'enum_class' is set
+        if ($enum_class === null || (is_array($enum_class) && count($enum_class) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $enum_class when calling fakeEnumEndpoint'
+            );
+        }
+        // verify the required parameter 'enum_class_array' is set
+        if ($enum_class_array === null || (is_array($enum_class_array) && count($enum_class_array) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $enum_class_array when calling fakeEnumEndpoint'
+            );
+        }
+        // verify the required parameter 'enum_class_map' is set
+        if ($enum_class_map === null || (is_array($enum_class_map) && count($enum_class_map) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $enum_class_map when calling fakeEnumEndpoint'
+            );
+        }
+
+        $resourcePath = '/fake/enum/endpoint';
+        $formParams = [];
+        $queryParams = [];
+        $headerParams = [];
+        $httpBody = null;
+        $multipart = false;
+
+        // query params
+        if ($enum_class !== null) {
+            if('form' === 'form' && is_array($enum_class)) {
+                foreach($enum_class as $key => $value) {
+                    $queryParams[$key] = $value;
+                }
+            }
+            else {
+                $queryParams['enum-class'] = $enum_class;
+            }
+        }
+        // query params
+        if ($enum_class_array !== null) {
+            if('form' === 'form' && is_array($enum_class_array)) {
+                foreach($enum_class_array as $key => $value) {
+                    $queryParams[$key] = $value;
+                }
+            }
+            else {
+                $queryParams['enum-class-array'] = $enum_class_array;
+            }
+        }
+        // query params
+        if ($enum_class_map !== null) {
+            if('form' === 'form' && is_array($enum_class_map)) {
+                foreach($enum_class_map as $key => $value) {
+                    $queryParams[$key] = $value;
+                }
+            }
+            else {
+                $queryParams['enum-class-map'] = $enum_class_map;
+            }
+        }
+
+
+
+
+        $headers = $this->headerSelector->selectHeaders(
+            ['application/json'],
+            '',
+            $multipart
+        );
+
+        // for model (json/xml)
+        if (count($formParams) > 0) {
+            if ($multipart) {
+                $multipartContents = [];
+                foreach ($formParams as $formParamName => $formParamValue) {
+                    $formParamValueItems = is_array($formParamValue) ? $formParamValue : [$formParamValue];
+                    foreach ($formParamValueItems as $formParamValueItem) {
+                        $multipartContents[] = [
+                            'name' => $formParamName,
+                            'contents' => $formParamValueItem
+                        ];
+                    }
+                }
+                // for HTTP post (form)
+                $httpBody = new MultipartStream($multipartContents);
+
+            } elseif ($headers['Content-Type'] === 'application/json') {
+                $httpBody = json_encode($formParams);
+
+            } else {
+                // for HTTP post (form)
+                $httpBody = ObjectSerializer::buildQuery($formParams);
+            }
+        }
+
+
+        $defaultHeaders = [];
+        if ($this->config->getUserAgent()) {
+            $defaultHeaders['User-Agent'] = $this->config->getUserAgent();
+        }
+
+        $headers = array_merge(
+            $defaultHeaders,
+            $headerParams,
+            $headers
+        );
+
+        $operationHost = $this->config->getHost();
+
+        $uri = $this->createUri($operationHost, $resourcePath, $queryParams);
+
+        return $this->createRequest('GET', $uri, $headers, $httpBody);
+    }
+
     /**
      * Operation fakeHealthGet
      *