diff --git a/modules/swagger-codegen/src/main/resources/php/model_generic.mustache b/modules/swagger-codegen/src/main/resources/php/model_generic.mustache
index c9300084b0f..ee90c746a68 100644
--- a/modules/swagger-codegen/src/main/resources/php/model_generic.mustache
+++ b/modules/swagger-codegen/src/main/resources/php/model_generic.mustache
@@ -205,13 +205,13 @@ class {{classname}} {{#parentSchema}}extends {{{parent}}} {{/parentSchema}}{{^pa
         {{/isEnum}}
         {{#hasValidation}}
         {{#maxLength}}
-        if ({{^required}}!is_null($this->container['{{name}}']) && {{/required}}(strlen($this->container['{{name}}']) > {{maxLength}})) {
+        if ({{^required}}!is_null($this->container['{{name}}']) && {{/required}}(mb_strlen($this->container['{{name}}']) > {{maxLength}})) {
             $invalidProperties[] = "invalid value for '{{name}}', the character length must be smaller than or equal to {{{maxLength}}}.";
         }
 
         {{/maxLength}}
         {{#minLength}}
-        if ({{^required}}!is_null($this->container['{{name}}']) && {{/required}}(strlen($this->container['{{name}}']) < {{minLength}})) {
+        if ({{^required}}!is_null($this->container['{{name}}']) && {{/required}}(mb_strlen($this->container['{{name}}']) < {{minLength}})) {
             $invalidProperties[] = "invalid value for '{{name}}', the character length must be bigger than or equal to {{{minLength}}}.";
         }
 
@@ -281,12 +281,12 @@ class {{classname}} {{#parentSchema}}extends {{{parent}}} {{/parentSchema}}{{^pa
         {{/isEnum}}
         {{#hasValidation}}
         {{#maxLength}}
-        if (strlen($this->container['{{name}}']) > {{maxLength}}) {
+        if (mb_strlen($this->container['{{name}}']) > {{maxLength}}) {
             return false;
         }
         {{/maxLength}}
         {{#minLength}}
-        if (strlen($this->container['{{name}}']) < {{minLength}}) {
+        if (mb_strlen($this->container['{{name}}']) < {{minLength}}) {
             return false;
         }
         {{/minLength}}
@@ -366,11 +366,11 @@ class {{classname}} {{#parentSchema}}extends {{{parent}}} {{/parentSchema}}{{^pa
         {{/isEnum}}
         {{#hasValidation}}
         {{#maxLength}}
-        if ({{^required}}!is_null(${{name}}) && {{/required}}(strlen(${{name}}) > {{maxLength}})) {
+        if ({{^required}}!is_null(${{name}}) && {{/required}}(mb_strlen(${{name}}) > {{maxLength}})) {
             throw new \InvalidArgumentException('invalid length for ${{name}} when calling {{classname}}.{{operationId}}, must be smaller than or equal to {{maxLength}}.');
         }{{/maxLength}}
         {{#minLength}}
-        if ({{^required}}!is_null(${{name}}) && {{/required}}(strlen(${{name}}) < {{minLength}})) {
+        if ({{^required}}!is_null(${{name}}) && {{/required}}(mb_strlen(${{name}}) < {{minLength}})) {
             throw new \InvalidArgumentException('invalid length for ${{name}} when calling {{classname}}.{{operationId}}, must be bigger than or equal to {{minLength}}.');
         }
         {{/minLength}}
diff --git a/samples/client/petstore-security-test/php/SwaggerClient-php/lib/ObjectSerializer.php b/samples/client/petstore-security-test/php/SwaggerClient-php/lib/ObjectSerializer.php
index c3f4590bc51..720eb97a8e5 100644
--- a/samples/client/petstore-security-test/php/SwaggerClient-php/lib/ObjectSerializer.php
+++ b/samples/client/petstore-security-test/php/SwaggerClient-php/lib/ObjectSerializer.php
@@ -271,7 +271,7 @@ class ObjectSerializer
             // determine file name
             if (array_key_exists('Content-Disposition', $httpHeaders) &&
                 preg_match('/inline; filename=[\'"]?([^\'"\s]+)[\'"]?$/i', $httpHeaders['Content-Disposition'], $match)) {
-                $filename = Configuration::getDefaultConfiguration()->getTempFolderPath() . self::sanitizeFilename($match[1]);
+                $filename = Configuration::getDefaultConfiguration()->getTempFolderPath() . DIRECTORY_SEPARATOR . self::sanitizeFilename($match[1]);
             } else {
                 $filename = tempnam(Configuration::getDefaultConfiguration()->getTempFolderPath(), '');
             }
diff --git a/samples/client/petstore/php/SwaggerClient-php/README.md b/samples/client/petstore/php/SwaggerClient-php/README.md
index 112c5b8ab08..2fd020297c7 100644
--- a/samples/client/petstore/php/SwaggerClient-php/README.md
+++ b/samples/client/petstore/php/SwaggerClient-php/README.md
@@ -80,6 +80,7 @@ All URIs are relative to *http://petstore.swagger.io:80/v2*
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
 *AnotherFakeApi* | [**testSpecialTags**](docs/Api/AnotherFakeApi.md#testspecialtags) | **PATCH** /another-fake/dummy | To test special tags
+*DefaultApi* | [**testBodyWithQueryParams**](docs/Api/DefaultApi.md#testbodywithqueryparams) | **PUT** /fake/body-with-query-params | 
 *FakeApi* | [**fakeOuterBooleanSerialize**](docs/Api/FakeApi.md#fakeouterbooleanserialize) | **POST** /fake/outer/boolean | 
 *FakeApi* | [**fakeOuterCompositeSerialize**](docs/Api/FakeApi.md#fakeoutercompositeserialize) | **POST** /fake/outer/composite | 
 *FakeApi* | [**fakeOuterNumberSerialize**](docs/Api/FakeApi.md#fakeouternumberserialize) | **POST** /fake/outer/number | 
diff --git a/samples/client/petstore/php/SwaggerClient-php/docs/Api/DefaultApi.md b/samples/client/petstore/php/SwaggerClient-php/docs/Api/DefaultApi.md
new file mode 100644
index 00000000000..0185322ccf2
--- /dev/null
+++ b/samples/client/petstore/php/SwaggerClient-php/docs/Api/DefaultApi.md
@@ -0,0 +1,57 @@
+# Swagger\Client\DefaultApi
+
+All URIs are relative to *http://petstore.swagger.io:80/v2*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**testBodyWithQueryParams**](DefaultApi.md#testBodyWithQueryParams) | **PUT** /fake/body-with-query-params | 
+
+
+# **testBodyWithQueryParams**
+> testBodyWithQueryParams($body, $query)
+
+
+
+### Example
+```php
+<?php
+require_once(__DIR__ . '/vendor/autoload.php');
+
+$apiInstance = new Swagger\Client\Api\DefaultApi(
+    // 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()
+);
+$body = new \Swagger\Client\Model\User(); // \Swagger\Client\Model\User | 
+$query = "query_example"; // string | 
+
+try {
+    $apiInstance->testBodyWithQueryParams($body, $query);
+} catch (Exception $e) {
+    echo 'Exception when calling DefaultApi->testBodyWithQueryParams: ', $e->getMessage(), PHP_EOL;
+}
+?>
+```
+
+### Parameters
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **body** | [**\Swagger\Client\Model\User**](../Model/User.md)|  |
+ **query** | **string**|  |
+
+### Return type
+
+void (empty response body)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: application/json
+ - **Accept**: Not defined
+
+[[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
+
diff --git a/samples/client/petstore/php/SwaggerClient-php/lib/Api/DefaultApi.php b/samples/client/petstore/php/SwaggerClient-php/lib/Api/DefaultApi.php
new file mode 100644
index 00000000000..a24fd708e39
--- /dev/null
+++ b/samples/client/petstore/php/SwaggerClient-php/lib/Api/DefaultApi.php
@@ -0,0 +1,339 @@
+<?php
+/**
+ * DefaultApi
+ * PHP version 5
+ *
+ * @category Class
+ * @package  Swagger\Client
+ * @author   Swagger Codegen team
+ * @link     https://github.com/swagger-api/swagger-codegen
+ */
+
+/**
+ * Swagger Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * OpenAPI spec version: 1.0.0
+ * Contact: apiteam@swagger.io
+ * Generated by: https://github.com/swagger-api/swagger-codegen.git
+ * Swagger Codegen version: 2.4.0-SNAPSHOT
+ */
+
+/**
+ * NOTE: This class is auto generated by the swagger code generator program.
+ * https://github.com/swagger-api/swagger-codegen
+ * Do not edit the class manually.
+ */
+
+namespace Swagger\Client\Api;
+
+use GuzzleHttp\Client;
+use GuzzleHttp\ClientInterface;
+use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Psr7\MultipartStream;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\RequestOptions;
+use Swagger\Client\ApiException;
+use Swagger\Client\Configuration;
+use Swagger\Client\HeaderSelector;
+use Swagger\Client\ObjectSerializer;
+
+/**
+ * DefaultApi Class Doc Comment
+ *
+ * @category Class
+ * @package  Swagger\Client
+ * @author   Swagger Codegen team
+ * @link     https://github.com/swagger-api/swagger-codegen
+ */
+class DefaultApi
+{
+    /**
+     * @var ClientInterface
+     */
+    protected $client;
+
+    /**
+     * @var Configuration
+     */
+    protected $config;
+
+    /**
+     * @var HeaderSelector
+     */
+    protected $headerSelector;
+
+    /**
+     * @param ClientInterface $client
+     * @param Configuration   $config
+     * @param HeaderSelector  $selector
+     */
+    public function __construct(
+        ClientInterface $client = null,
+        Configuration $config = null,
+        HeaderSelector $selector = null
+    ) {
+        $this->client = $client ?: new Client();
+        $this->config = $config ?: new Configuration();
+        $this->headerSelector = $selector ?: new HeaderSelector();
+    }
+
+    /**
+     * @return Configuration
+     */
+    public function getConfig()
+    {
+        return $this->config;
+    }
+
+    /**
+     * Operation testBodyWithQueryParams
+     *
+     * @param  \Swagger\Client\Model\User $body body (required)
+     * @param  string $query query (required)
+     *
+     * @throws \Swagger\Client\ApiException on non-2xx response
+     * @throws \InvalidArgumentException
+     * @return void
+     */
+    public function testBodyWithQueryParams($body, $query)
+    {
+        $this->testBodyWithQueryParamsWithHttpInfo($body, $query);
+    }
+
+    /**
+     * Operation testBodyWithQueryParamsWithHttpInfo
+     *
+     * @param  \Swagger\Client\Model\User $body (required)
+     * @param  string $query (required)
+     *
+     * @throws \Swagger\Client\ApiException on non-2xx response
+     * @throws \InvalidArgumentException
+     * @return array of null, HTTP status code, HTTP response headers (array of strings)
+     */
+    public function testBodyWithQueryParamsWithHttpInfo($body, $query)
+    {
+        $returnType = '';
+        $request = $this->testBodyWithQueryParamsRequest($body, $query);
+
+        try {
+            $options = $this->createHttpClientOption();
+            try {
+                $response = $this->client->send($request, $options);
+            } catch (RequestException $e) {
+                throw new ApiException(
+                    "[{$e->getCode()}] {$e->getMessage()}",
+                    $e->getCode(),
+                    $e->getResponse() ? $e->getResponse()->getHeaders() : null,
+                    $e->getResponse() ? $e->getResponse()->getBody()->getContents() : null
+                );
+            }
+
+            $statusCode = $response->getStatusCode();
+
+            if ($statusCode < 200 || $statusCode > 299) {
+                throw new ApiException(
+                    sprintf(
+                        '[%d] Error connecting to the API (%s)',
+                        $statusCode,
+                        $request->getUri()
+                    ),
+                    $statusCode,
+                    $response->getHeaders(),
+                    $response->getBody()
+                );
+            }
+
+            return [null, $statusCode, $response->getHeaders()];
+
+        } catch (ApiException $e) {
+            switch ($e->getCode()) {
+            }
+            throw $e;
+        }
+    }
+
+    /**
+     * Operation testBodyWithQueryParamsAsync
+     *
+     * 
+     *
+     * @param  \Swagger\Client\Model\User $body (required)
+     * @param  string $query (required)
+     *
+     * @throws \InvalidArgumentException
+     * @return \GuzzleHttp\Promise\PromiseInterface
+     */
+    public function testBodyWithQueryParamsAsync($body, $query)
+    {
+        return $this->testBodyWithQueryParamsAsyncWithHttpInfo($body, $query)
+            ->then(
+                function ($response) {
+                    return $response[0];
+                }
+            );
+    }
+
+    /**
+     * Operation testBodyWithQueryParamsAsyncWithHttpInfo
+     *
+     * 
+     *
+     * @param  \Swagger\Client\Model\User $body (required)
+     * @param  string $query (required)
+     *
+     * @throws \InvalidArgumentException
+     * @return \GuzzleHttp\Promise\PromiseInterface
+     */
+    public function testBodyWithQueryParamsAsyncWithHttpInfo($body, $query)
+    {
+        $returnType = '';
+        $request = $this->testBodyWithQueryParamsRequest($body, $query);
+
+        return $this->client
+            ->sendAsync($request, $this->createHttpClientOption())
+            ->then(
+                function ($response) use ($returnType) {
+                    return [null, $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(),
+                        $response->getBody()
+                    );
+                }
+            );
+    }
+
+    /**
+     * Create request for operation 'testBodyWithQueryParams'
+     *
+     * @param  \Swagger\Client\Model\User $body (required)
+     * @param  string $query (required)
+     *
+     * @throws \InvalidArgumentException
+     * @return \GuzzleHttp\Psr7\Request
+     */
+    protected function testBodyWithQueryParamsRequest($body, $query)
+    {
+        // verify the required parameter 'body' is set
+        if ($body === null || (is_array($body) && count($body) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $body when calling testBodyWithQueryParams'
+            );
+        }
+        // verify the required parameter 'query' is set
+        if ($query === null || (is_array($query) && count($query) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $query when calling testBodyWithQueryParams'
+            );
+        }
+
+        $resourcePath = '/fake/body-with-query-params';
+        $formParams = [];
+        $queryParams = [];
+        $headerParams = [];
+        $httpBody = '';
+        $multipart = false;
+
+        // query params
+        if ($query !== null) {
+            $queryParams['query'] = ObjectSerializer::toQueryValue($query);
+        }
+
+
+        // body params
+        $_tempBody = null;
+        if (isset($body)) {
+            $_tempBody = $body;
+        }
+
+        if ($multipart) {
+            $headers = $this->headerSelector->selectHeadersForMultipart(
+                []
+            );
+        } else {
+            $headers = $this->headerSelector->selectHeaders(
+                [],
+                ['application/json']
+            );
+        }
+
+        // for model (json/xml)
+        if (isset($_tempBody)) {
+            // $_tempBody is the method argument, if present
+            $httpBody = $_tempBody;
+            // \stdClass has no __toString(), so we should encode it manually
+            if ($httpBody instanceof \stdClass && $headers['Content-Type'] === 'application/json') {
+                $httpBody = \GuzzleHttp\json_encode($httpBody);
+            }
+        } elseif (count($formParams) > 0) {
+            if ($multipart) {
+                $multipartContents = [];
+                foreach ($formParams as $formParamName => $formParamValue) {
+                    $multipartContents[] = [
+                        'name' => $formParamName,
+                        'contents' => $formParamValue
+                    ];
+                }
+                // for HTTP post (form)
+                $httpBody = new MultipartStream($multipartContents);
+
+            } elseif ($headers['Content-Type'] === 'application/json') {
+                $httpBody = \GuzzleHttp\json_encode($formParams);
+
+            } else {
+                // for HTTP post (form)
+                $httpBody = \GuzzleHttp\Psr7\build_query($formParams);
+            }
+        }
+
+
+        $defaultHeaders = [];
+        if ($this->config->getUserAgent()) {
+            $defaultHeaders['User-Agent'] = $this->config->getUserAgent();
+        }
+
+        $headers = array_merge(
+            $defaultHeaders,
+            $headerParams,
+            $headers
+        );
+
+        $query = \GuzzleHttp\Psr7\build_query($queryParams);
+        return new Request(
+            'PUT',
+            $this->config->getHost() . $resourcePath . ($query ? "?{$query}" : ''),
+            $headers,
+            $httpBody
+        );
+    }
+
+    /**
+     * Create http client option
+     *
+     * @throws \RuntimeException on file opening failure
+     * @return array of http client options
+     */
+    protected function createHttpClientOption()
+    {
+        $options = [];
+        if ($this->config->getDebug()) {
+            $options[RequestOptions::DEBUG] = fopen($this->config->getDebugFile(), 'a');
+            if (!$options[RequestOptions::DEBUG]) {
+                throw new \RuntimeException('Failed to open the debug file: ' . $this->config->getDebugFile());
+            }
+        }
+
+        return $options;
+    }
+}
diff --git a/samples/client/petstore/php/SwaggerClient-php/lib/Model/FormatTest.php b/samples/client/petstore/php/SwaggerClient-php/lib/Model/FormatTest.php
index a8c74e7b761..8e9d1e45237 100644
--- a/samples/client/petstore/php/SwaggerClient-php/lib/Model/FormatTest.php
+++ b/samples/client/petstore/php/SwaggerClient-php/lib/Model/FormatTest.php
@@ -321,11 +321,11 @@ class FormatTest implements ModelInterface, ArrayAccess
         if ($this->container['password'] === null) {
             $invalidProperties[] = "'password' can't be null";
         }
-        if ((strlen($this->container['password']) > 64)) {
+        if ((mb_strlen($this->container['password']) > 64)) {
             $invalidProperties[] = "invalid value for 'password', the character length must be smaller than or equal to 64.";
         }
 
-        if ((strlen($this->container['password']) < 10)) {
+        if ((mb_strlen($this->container['password']) < 10)) {
             $invalidProperties[] = "invalid value for 'password', the character length must be bigger than or equal to 10.";
         }
 
@@ -389,10 +389,10 @@ class FormatTest implements ModelInterface, ArrayAccess
         if ($this->container['password'] === null) {
             return false;
         }
-        if (strlen($this->container['password']) > 64) {
+        if (mb_strlen($this->container['password']) > 64) {
             return false;
         }
-        if (strlen($this->container['password']) < 10) {
+        if (mb_strlen($this->container['password']) < 10) {
             return false;
         }
         return true;
@@ -756,10 +756,10 @@ class FormatTest implements ModelInterface, ArrayAccess
      */
     public function setPassword($password)
     {
-        if ((strlen($password) > 64)) {
+        if ((mb_strlen($password) > 64)) {
             throw new \InvalidArgumentException('invalid length for $password when calling FormatTest., must be smaller than or equal to 64.');
         }
-        if ((strlen($password) < 10)) {
+        if ((mb_strlen($password) < 10)) {
             throw new \InvalidArgumentException('invalid length for $password when calling FormatTest., must be bigger than or equal to 10.');
         }
 
diff --git a/samples/client/petstore/php/SwaggerClient-php/test/Api/DefaultApiTest.php b/samples/client/petstore/php/SwaggerClient-php/test/Api/DefaultApiTest.php
new file mode 100644
index 00000000000..f5d11998adf
--- /dev/null
+++ b/samples/client/petstore/php/SwaggerClient-php/test/Api/DefaultApiTest.php
@@ -0,0 +1,83 @@
+<?php
+/**
+ * DefaultApiTest
+ * PHP version 5
+ *
+ * @category Class
+ * @package  Swagger\Client
+ * @author   Swagger Codegen team
+ * @link     https://github.com/swagger-api/swagger-codegen
+ */
+
+/**
+ * Swagger Petstore
+ *
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * OpenAPI spec version: 1.0.0
+ * Contact: apiteam@swagger.io
+ * Generated by: https://github.com/swagger-api/swagger-codegen.git
+ * Swagger Codegen version: 2.4.0-SNAPSHOT
+ */
+
+/**
+ * NOTE: This class is auto generated by the swagger code generator program.
+ * https://github.com/swagger-api/swagger-codegen
+ * Please update the test case below to test the endpoint.
+ */
+
+namespace Swagger\Client;
+
+use \Swagger\Client\Configuration;
+use \Swagger\Client\ApiException;
+use \Swagger\Client\ObjectSerializer;
+
+/**
+ * DefaultApiTest Class Doc Comment
+ *
+ * @category Class
+ * @package  Swagger\Client
+ * @author   Swagger Codegen team
+ * @link     https://github.com/swagger-api/swagger-codegen
+ */
+class DefaultApiTest extends \PHPUnit_Framework_TestCase
+{
+
+    /**
+     * Setup before running any test cases
+     */
+    public static function setUpBeforeClass()
+    {
+    }
+
+    /**
+     * Setup before running each test case
+     */
+    public function setUp()
+    {
+    }
+
+    /**
+     * Clean up after running each test case
+     */
+    public function tearDown()
+    {
+    }
+
+    /**
+     * Clean up after running all test cases
+     */
+    public static function tearDownAfterClass()
+    {
+    }
+
+    /**
+     * Test case for testBodyWithQueryParams
+     *
+     * .
+     *
+     */
+    public function testTestBodyWithQueryParams()
+    {
+    }
+}
diff --git a/samples/client/petstore/php/SwaggerClient-php/tests/FormatTestTest.php b/samples/client/petstore/php/SwaggerClient-php/tests/FormatTestTest.php
new file mode 100644
index 00000000000..e91222a1686
--- /dev/null
+++ b/samples/client/petstore/php/SwaggerClient-php/tests/FormatTestTest.php
@@ -0,0 +1,26 @@
+<?php
+
+use Swagger\Client\Model\FormatTest;
+
+class FormatTestTest extends \PHPUnit_Framework_TestCase
+{
+    public function testCountTheLengthOfMultiByteStringsCorrectly()
+    {
+        $the64MultiByteStrings = '１２３４５６７８９０１２３４５６７８９０１２３４５６７８９０１２３４５６７８９０１２３４５６７８９０１２３４５６７８９０１２３';
+
+        // Pass the string via constructor.
+        $formatTest = new FormatTest([
+            'password' => $the64MultiByteStrings,
+            // mandatory parameters
+            'number' => 500,
+            'byte' => base64_encode('test'),
+            'date' => new DateTime(),
+        ]);
+
+        $this->assertEmpty($formatTest->listInvalidProperties());
+
+        // Pass the strings via setter.
+        // Throws InvalidArgumentException if it doesn't count the length correctly.
+        $formatTest->setPassword($the64MultiByteStrings);
+    }
+}