diff --git a/.travis.yml b/.travis.yml
index cf26742..26a4ed1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,6 @@ php:
     - 7.0
     - 5.6
     - 5.5
-    - 5.4
     - hhvm
 
 install:
diff --git a/Goutte/Client.php b/Goutte/Client.php
index a4ebfc2..7d576bb 100644
--- a/Goutte/Client.php
+++ b/Goutte/Client.php
@@ -13,10 +13,9 @@
 
 use GuzzleHttp\Client as GuzzleClient;
 use GuzzleHttp\ClientInterface as GuzzleClientInterface;
+use GuzzleHttp\Cookie\CookieJar;
 use GuzzleHttp\Exception\RequestException;
-use GuzzleHttp\Message\RequestInterface;
-use GuzzleHttp\Message\Response as GuzzleResponse;
-use GuzzleHttp\Post\PostFile;
+use Psr\Http\Message\ResponseInterface;
 use Symfony\Component\BrowserKit\Client as BaseClient;
 use Symfony\Component\BrowserKit\Response;
 
@@ -25,6 +24,7 @@
  *
  * @author Fabien Potencier <fabien.potencier@symfony-project.com>
  * @author Michael Dowling <michael@guzzlephp.org>
+ * @author Charles Sarrazin <charles@sarraz.in>
  */
 class Client extends BaseClient
 {
@@ -90,44 +90,44 @@ protected function doRequest($request)
             }
         }
 
-        $body = null;
+        $cookies = CookieJar::fromArray(
+            $this->getCookieJar()->allRawValues($request->getUri()),
+            $request->getServer()['HTTP_HOST']
+        );
+
+        $requestOptions = array(
+            'cookies' => $cookies,
+            'allow_redirects' => false,
+            'auth' => $this->auth,
+        );
+
         if (!in_array($request->getMethod(), array('GET', 'HEAD'))) {
             if (null !== $request->getContent()) {
-                $body = $request->getContent();
+                $requestOptions['body'] = $request->getContent();
             } else {
-                $body = $request->getParameters();
+                $requestOptions['form_params'] = $request->getParameters();
+
+                if ($files = $request->getFiles()) {
+                    $requestOptions['multipart'] = [];
+                    $this->addPostFiles($files, $requestOptions['multipart']);
+                }
             }
         }
 
-        $this->getClient()->setDefaultOption('auth', $this->auth);
-
-        $requestOptions = array(
-            'body' => $body,
-            'cookies' => $this->getCookieJar()->allRawValues($request->getUri()),
-            'allow_redirects' => false,
-        );
-
         if (!empty($headers)) {
             $requestOptions['headers'] = $headers;
         }
 
-        $guzzleRequest = $this->getClient()->createRequest(
-            $request->getMethod(),
-            $request->getUri(),
-            $requestOptions
-        );
+        $method = $request->getMethod();
+        $uri = $request->getUri();
 
         foreach ($this->headers as $name => $value) {
-            $guzzleRequest->setHeader($name, $value);
-        }
-
-        if ('POST' == $request->getMethod() || 'PUT' == $request->getMethod() && $request->getFiles()) {
-            $this->addPostFiles($guzzleRequest, $request->getFiles());
+            $requestOptions['headers'][$name] = $value;
         }
 
         // Let BrowserKit handle redirects
         try {
-            $response = $this->getClient()->send($guzzleRequest);
+            $response = $this->getClient()->request($method, $uri, $requestOptions);
         } catch (RequestException $e) {
             $response = $e->getResponse();
             if (null === $response) {
@@ -138,33 +138,45 @@ protected function doRequest($request)
         return $this->createResponse($response);
     }
 
-    protected function addPostFiles(RequestInterface $request, array $files, $arrayName = '')
+    protected function addPostFiles(array $files, array &$multipart, $arrayName = '')
     {
+        if (empty($files)) {
+            return;
+        }
+
         foreach ($files as $name => $info) {
             if (!empty($arrayName)) {
                 $name = $arrayName.'['.$name.']';
             }
 
+            $file = [
+                'name' => $name,
+            ];
+
             if (is_array($info)) {
                 if (isset($info['tmp_name'])) {
                     if ('' !== $info['tmp_name']) {
-                        $request->getBody()->addFile(new PostFile($name, fopen($info['tmp_name'], 'r'), isset($info['name']) ? $info['name'] : null));
+                        $file['contents'] = fopen($info['tmp_name'], 'r');
+                        if (isset($info['name'])) {
+                            $file['filename'] = $info['name'];
+                        }
                     } else {
                         continue;
                     }
                 } else {
-                    $this->addPostFiles($request, $info, $name);
+                    $this->addPostFiles($info, $multipart, $name);
+                    continue;
                 }
             } else {
-                $request->getBody()->addFile(new PostFile($name, fopen($info, 'r')));
+                $file['contents'] = fopen($info, 'r');
             }
+
+            $multipart[] = $file;
         }
     }
 
-    protected function createResponse(GuzzleResponse $response)
+    protected function createResponse(ResponseInterface $response)
     {
-        $headers = $response->getHeaders();
-
-        return new Response($response->getBody(true), $response->getStatusCode(), $headers);
+        return new Response((string) $response->getBody(), $response->getStatusCode(), $response->getHeaders());
     }
 }
diff --git a/Goutte/Tests/ClientTest.php b/Goutte/Tests/ClientTest.php
index da2e47c..d8ef647 100644
--- a/Goutte/Tests/ClientTest.php
+++ b/Goutte/Tests/ClientTest.php
@@ -14,31 +14,34 @@
 use Goutte\Client;
 use GuzzleHttp\Client as GuzzleClient;
 use GuzzleHttp\Exception\RequestException;
-use GuzzleHttp\Message\Response as GuzzleResponse;
-use GuzzleHttp\Stream\Stream;
-use GuzzleHttp\Subscriber\History;
-use GuzzleHttp\Subscriber\Mock;
-use GuzzleHttp\Post\PostFile;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response as GuzzleResponse;
+use GuzzleHttp\Middleware;
 use Symfony\Component\BrowserKit\Cookie;
 
 /**
- * Goutte Client Test
+ * Goutte Client Test.
  *
  * @author Michael Dowling <michael@guzzlephp.org>
+ * @author Charles Sarrazin <charles@sarraz.in>
  */
 class ClientTest extends \PHPUnit_Framework_TestCase
 {
     protected $history;
+    /** @var MockHandler */
     protected $mock;
 
-    protected function getGuzzle()
+    protected function getGuzzle(array $responses = [])
     {
-        $this->history = new History();
-        $this->mock = new Mock();
-        $this->mock->addResponse(new GuzzleResponse(200, array(), Stream::factory('<html><body><p>Hi</p></body></html>')));
-        $guzzle = new GuzzleClient(array('redirect.disable' => true, 'base_url' => ''));
-        $guzzle->getEmitter()->attach($this->mock);
-        $guzzle->getEmitter()->attach($this->history);
+        if (empty($responses)) {
+            $responses = [new GuzzleResponse(200, [], '<html><body><p>Hi</p></body></html>')];
+        }
+        $this->mock = new MockHandler($responses);
+        $handlerStack = HandlerStack::create($this->mock);
+        $this->history = [];
+        $handlerStack->push(Middleware::history($this->history));
+        $guzzle = new GuzzleClient(array('redirect.disable' => true, 'base_uri' => '', 'handler' => $handlerStack));
 
         return $guzzle;
     }
@@ -63,8 +66,8 @@ public function testUsesCustomHeaders()
         $client = new Client();
         $client->setClient($guzzle);
         $client->setHeader('X-Test', 'test');
-        $crawler = $client->request('GET', 'http://www.example.com/');
-        $this->assertEquals('test', $this->history->getLastRequest()->getHeader('X-Test'));
+        $client->request('GET', 'http://www.example.com/');
+        $this->assertEquals('test', end($this->history)['request']->getHeaderLine('X-Test'));
     }
 
     public function testCustomUserAgent()
@@ -73,8 +76,8 @@ public function testCustomUserAgent()
         $client = new Client();
         $client->setClient($guzzle);
         $client->setHeader('User-Agent', 'foo');
-        $crawler = $client->request('GET', 'http://www.example.com/');
-        $this->assertEquals('foo', $this->history->getLastRequest()->getHeader('User-Agent'));
+        $client->request('GET', 'http://www.example.com/');
+        $this->assertEquals('Symfony2 BrowserKit, foo', end($this->history)['request']->getHeaderLine('User-Agent'));
     }
 
     public function testUsesAuth()
@@ -83,11 +86,9 @@ public function testUsesAuth()
         $client = new Client();
         $client->setClient($guzzle);
         $client->setAuth('me', '**');
-        $crawler = $client->request('GET', 'http://www.example.com/');
-        $request = $this->history->getLastRequest();
-        $this->assertEquals('me', $request->getConfig()->get('auth')[0]);
-        $this->assertEquals('**', $request->getConfig()->get('auth')[1]);
-        $this->assertEquals('basic', $request->getConfig()->get('auth')[2]);
+        $client->request('GET', 'http://www.example.com/');
+        $request = end($this->history)['request'];
+        $this->assertEquals('Basic bWU6Kio=', $request->getHeaderLine('Authorization'));
     }
 
     public function testResetsAuth()
@@ -97,10 +98,9 @@ public function testResetsAuth()
         $client->setClient($guzzle);
         $client->setAuth('me', '**');
         $client->resetAuth();
-        $crawler = $client->request('GET', 'http://www.example.com/');
-        $request = $this->history->getLastRequest();
-        $this->assertNull($request->getConfig()->get('auth')[0]);
-        $this->assertNull($request->getConfig()->get('auth')[1]);
+        $client->request('GET', 'http://www.example.com/');
+        $request = end($this->history)['request'];
+        $this->assertEquals('', $request->getHeaderLine('authorization'));
     }
 
     public function testUsesCookies()
@@ -109,9 +109,9 @@ public function testUsesCookies()
         $client = new Client();
         $client->setClient($guzzle);
         $client->getCookieJar()->set(new Cookie('test', '123'));
-        $crawler = $client->request('GET', 'http://www.example.com/');
-        $request = $this->history->getLastRequest();
-        $this->assertEquals('test=123', $request->getHeader('Cookie'));
+        $client->request('GET', 'http://www.example.com/');
+        $request = end($this->history)['request'];
+        $this->assertEquals('test=123', $request->getHeaderLine('Cookie'));
     }
 
     public function testUsesPostFiles()
@@ -122,18 +122,20 @@ public function testUsesPostFiles()
         $files = array(
             'test' => array(
                 'name' => 'test.txt',
-                'tmp_name' => __FILE__,
+                'tmp_name' => __DIR__.'/fixtures.txt',
             ),
         );
 
-        $crawler = $client->request('POST', 'http://www.example.com/', array(), $files);
-        $request = $this->history->getLastRequest();
+        $client->request('POST', 'http://www.example.com/', array(), $files);
+        $request = end($this->history)['request'];
 
-        $files = $request->getBody()->getFiles();
-        $this->assertFile(reset($files), 'test', 'test.txt', array(
-          'Content-Type' => 'text/plain',
-          'Content-Disposition' => 'form-data; filename="test.txt"; name="test"',
-        ));
+        $stream = $request->getBody();
+        $boundary = $stream->getBoundary();
+        $this->assertEquals(
+            "--$boundary\r\nContent-Disposition: form-data; name=\"test\"; filename=\"test.txt\"\r\nContent-Length: 4\r\n"
+            ."Content-Type: text/plain\r\n\r\nfoo\n\r\n--$boundary--\r\n",
+            $stream->getContents()
+        );
     }
 
     public function testUsesPostNamedFiles()
@@ -142,16 +144,19 @@ public function testUsesPostNamedFiles()
         $client = new Client();
         $client->setClient($guzzle);
         $files = array(
-            'test' => __FILE__,
+            'test' => __DIR__.'/fixtures.txt',
         );
 
-        $crawler = $client->request('POST', 'http://www.example.com/', array(), $files);
-        $request = $this->history->getLastRequest();
-        $files = $request->getBody()->getFiles();
-        $this->assertFile(reset($files), 'test', __FILE__, array(
-          'Content-Type' => 'text/x-php',
-          'Content-Disposition' => 'form-data; filename="ClientTest.php"; name="test"',
-        ));
+        $client->request('POST', 'http://www.example.com/', array(), $files);
+        $request = end($this->history)['request'];
+
+        $stream = $request->getBody();
+        $boundary = $stream->getBoundary();
+        $this->assertEquals(
+            "--$boundary\r\nContent-Disposition: form-data; name=\"test\"; filename=\"fixtures.txt\"\r\nContent-Length: 4\r\n"
+            ."Content-Type: text/plain\r\n\r\nfoo\n\r\n--$boundary--\r\n",
+            $stream->getContents()
+        );
     }
 
     public function testUsesPostFilesNestedFields()
@@ -163,18 +168,21 @@ public function testUsesPostFilesNestedFields()
             'form' => array(
                 'test' => array(
                     'name' => 'test.txt',
-                    'tmp_name' => __FILE__,
+                    'tmp_name' => __DIR__.'/fixtures.txt',
                 ),
             ),
         );
 
-        $crawler = $client->request('POST', 'http://www.example.com/', array(), $files);
-        $request = $this->history->getLastRequest();
-        $files = $request->getBody()->getFiles();
-        $this->assertFile(reset($files), 'form[test]', 'test.txt', array(
-            'Content-Type' => 'text/plain',
-            'Content-Disposition' => 'form-data; filename="test.txt"; name="form[test]"',
-        ));
+        $client->request('POST', 'http://www.example.com/', array(), $files);
+        $request = end($this->history)['request'];
+
+        $stream = $request->getBody();
+        $boundary = $stream->getBoundary();
+        $this->assertEquals(
+            "--$boundary\r\nContent-Disposition: form-data; name=\"form[test]\"; filename=\"test.txt\"\r\nContent-Length: 4\r\n"
+            ."Content-Type: text/plain\r\n\r\nfoo\n\r\n--$boundary--\r\n",
+            $stream->getContents()
+        );
     }
 
     public function testUsesPostFilesOnClientSide()
@@ -183,16 +191,19 @@ public function testUsesPostFilesOnClientSide()
         $client = new Client();
         $client->setClient($guzzle);
         $files = array(
-            'test' => __FILE__,
+            'test' => __DIR__.'/fixtures.txt',
         );
 
-        $crawler = $client->request('POST', 'http://www.example.com/', array(), $files);
-        $request = $this->history->getLastRequest();
-        $files = $request->getBody()->getFiles();
-        $this->assertFile(reset($files), 'test', __FILE__, array(
-          'Content-Type' => 'text/x-php',
-          'Content-Disposition' => 'form-data; filename="ClientTest.php"; name="test"',
-        ));
+        $client->request('POST', 'http://www.example.com/', array(), $files);
+        $request = end($this->history)['request'];
+
+        $stream = $request->getBody();
+        $boundary = $stream->getBoundary();
+        $this->assertEquals(
+            "--$boundary\r\nContent-Disposition: form-data; name=\"test\"; filename=\"fixtures.txt\"\r\nContent-Length: 4\r\n"
+            ."Content-Type: text/plain\r\n\r\nfoo\n\r\n--$boundary--\r\n",
+            $stream->getContents()
+        );
     }
 
     public function testUsesPostFilesUploadError()
@@ -210,10 +221,12 @@ public function testUsesPostFilesUploadError()
             ),
         );
 
-        $crawler = $client->request('POST', 'http://www.example.com/', array(), $files);
-        $request = $this->history->getLastRequest();
+        $client->request('POST', 'http://www.example.com/', array(), $files);
+        $request = end($this->history)['request'];
+        $stream = $request->getBody();
+        $boundary = $stream->getBoundary();
 
-        $this->assertEquals(array(), $request->getBody()->getFiles());
+        $this->assertEquals("--$boundary--\r\n", $stream->getContents());
     }
 
     public function testCreatesResponse()
@@ -227,13 +240,12 @@ public function testCreatesResponse()
 
     public function testHandlesRedirectsCorrectly()
     {
-        $guzzle = $this->getGuzzle();
-
-        $this->mock->clearQueue();
-        $this->mock->addResponse(new GuzzleResponse(301, array(
-            'Location' => 'http://www.example.com/',
-        )));
-        $this->mock->addResponse(new GuzzleResponse(200, [], Stream::factory('<html><body><p>Test</p></body></html>')));
+        $guzzle = $this->getGuzzle([
+            new GuzzleResponse(301, array(
+                'Location' => 'http://www.example.com/',
+            )),
+            new GuzzleResponse(200, [], '<html><body><p>Test</p></body></html>'),
+        ]);
 
         $client = new Client();
         $client->setClient($guzzle);
@@ -247,12 +259,11 @@ public function testHandlesRedirectsCorrectly()
 
     public function testConvertsGuzzleHeadersToArrays()
     {
-        $guzzle = $this->getGuzzle();
-
-        $this->mock->clearQueue();
-        $this->mock->addResponse(new GuzzleResponse(200, array(
-            'Date' => 'Tue, 04 Jun 2013 13:22:41 GMT',
-        )));
+        $guzzle = $this->getGuzzle([
+            new GuzzleResponse(200, array(
+                'Date' => 'Tue, 04 Jun 2013 13:22:41 GMT',
+            )),
+        ]);
 
         $client = new Client();
         $client->setClient($guzzle);
@@ -260,48 +271,30 @@ public function testConvertsGuzzleHeadersToArrays()
         $response = $client->getResponse();
         $headers = $response->getHeaders();
 
-        $this->assertInternalType("array", array_shift($headers), "Header not converted from Guzzle\Http\Message\Header to array");
+        $this->assertInternalType('array', array_shift($headers), 'Header not converted from Guzzle\Http\Message\Header to array');
     }
 
     public function testNullResponseException()
     {
         $this->setExpectedException('GuzzleHttp\Exception\RequestException');
-        $guzzle = $this->getGuzzle();
-        $this->mock->clearQueue();
-        $exception = new RequestException('', $this->getMock('GuzzleHttp\Message\RequestInterface'));
-        $this->mock->addException($exception);
+        $guzzle = $this->getGuzzle([
+            new RequestException('', $this->getMock('Psr\Http\Message\RequestInterface')),
+        ]);
         $client = new Client();
         $client->setClient($guzzle);
         $client->request('GET', 'http://www.example.com/');
-        $response = $client->getResponse();
-    }
-
-    protected function assertFile(PostFile $postFile, $fieldName, $fileName, $headers)
-    {
-        $this->assertEquals($postFile->getName(), $fieldName);
-        $this->assertEquals($postFile->getFilename(), $fileName);
-
-        $postFileHeaders = $postFile->getHeaders();
-
-        // Note: Sort 'Content-Disposition' values before comparing, because the order changed in Guzzle 4.2.2
-        $postFileHeaders['Content-Disposition'] = explode('; ', $postFileHeaders['Content-Disposition']);
-        sort($postFileHeaders['Content-Disposition']);
-        $headers['Content-Disposition'] = explode('; ', $headers['Content-Disposition']);
-        sort($headers['Content-Disposition']);
-
-        $this->assertEquals($postFileHeaders, $headers);
+        $client->getResponse();
     }
 
     public function testHttps()
     {
-        $guzzle = $this->getGuzzle();
+        $guzzle = $this->getGuzzle([
+            new GuzzleResponse(200, [], '<html><body><p>Test</p></body></html>'),
+        ]);
 
-        $this->mock->clearQueue();
-        $this->mock->addResponse(new GuzzleResponse(200, [], Stream::factory('<html><body><p>Test</p></body></html>')));
         $client = new Client();
         $client->setClient($guzzle);
         $crawler = $client->request('GET', 'https://www.example.com/');
-        $this->assertEquals('https', $this->history->getLastRequest()->getScheme());
         $this->assertEquals('Test', $crawler->filter('p')->text());
     }
 
@@ -313,7 +306,7 @@ public function testCustomUserAgentConstructor()
           'HTTP_USER_AGENT' => 'SomeHost',
         ]);
         $client->setClient($guzzle);
-        $crawler = $client->request('GET', 'http://www.example.com/');
-        $this->assertEquals('SomeHost', $this->history->getLastRequest()->getHeader('User-Agent'));
+        $client->request('GET', 'http://www.example.com/');
+        $this->assertEquals('SomeHost', end($this->history)['request']->getHeaderLine('User-Agent'));
     }
 }
diff --git a/Goutte/Tests/fixtures.txt b/Goutte/Tests/fixtures.txt
new file mode 100644
index 0000000..257cc56
--- /dev/null
+++ b/Goutte/Tests/fixtures.txt
@@ -0,0 +1 @@
+foo
diff --git a/README.rst b/README.rst
index a6aab89..c1ade39 100644
--- a/README.rst
+++ b/README.rst
@@ -9,10 +9,11 @@ responses.
 Requirements
 ------------
 
-Goutte depends on PHP 5.4+ and Guzzle 4+.
+Goutte depends on PHP 5.5+ and Guzzle 6+.
 
 .. tip::
 
+    If you need support for PHP 5.4 or Guzzle 4-5, use Goutte 2.x.
     If you need support for PHP 5.3 or Guzzle 3, use Goutte 1.x.
 
 Installation
diff --git a/composer.json b/composer.json
index 63d87e7..ca5be44 100644
--- a/composer.json
+++ b/composer.json
@@ -12,18 +12,18 @@
         }
     ],
     "require": {
-        "php": ">=5.4.0",
+        "php": ">=5.5.0",
         "symfony/browser-kit": "~2.1",
         "symfony/css-selector": "~2.1",
         "symfony/dom-crawler": "~2.1",
-        "guzzlehttp/guzzle": ">=4,<6"
+        "guzzlehttp/guzzle": "^6.0"
     },
     "autoload": {
         "psr-4": { "Goutte\\": "Goutte" }
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "2.0-dev"
+            "dev-master": "3.0-dev"
         }
     }
 }