diff --git a/composer.json b/composer.json
index f0b16ac6..979383cd 100644
--- a/composer.json
+++ b/composer.json
@@ -17,10 +17,11 @@
   ],
   "require": {
     "php": ">=5.4",
-    "guzzlehttp/guzzle": "^6.2"
+    "guzzlehttp/guzzle": "^5.3",
+    "indigophp/hash-compat": "^1.1"
   },
   "require-dev": {
-    "phpunit/phpunit": "^5.3.2",
+    "phpunit/phpunit": "^4.8.24",
     "phpmd/phpmd": "~2.4",
     "squizlabs/php_codesniffer": "~2.6",
     "apigen/apigen": "~4.1"
diff --git a/src/LINEBot/HTTPClient/GuzzleHTTPClient.php b/src/LINEBot/HTTPClient/GuzzleHTTPClient.php
index f8589a6b..90c9d274 100644
--- a/src/LINEBot/HTTPClient/GuzzleHTTPClient.php
+++ b/src/LINEBot/HTTPClient/GuzzleHTTPClient.php
@@ -18,6 +18,7 @@
 
 use GuzzleHttp\Client;
 use GuzzleHttp\Exception\BadResponseException;
+use GuzzleHttp\Stream\Stream;
 use LINE\LINEBot;
 use LINE\LINEBot\DownloadedContents;
 use LINE\LINEBot\Exception\ContentsDownloadingFailedException;
@@ -67,7 +68,7 @@ public function __construct(array $args)
     public function get($url)
     {
         try {
-            $res = $this->guzzle->request('GET', $url, ['headers' => $this->credentials()]);
+            $res = $this->guzzle->get($url, ['headers' => $this->credentials()]);
         } catch (BadResponseException $e) {
             $res = $e->getResponse();
         }
@@ -108,7 +109,7 @@ public function post($url, array $data)
         ]);
 
         try {
-            $res = $this->guzzle->request('POST', $url, [
+            $res = $this->guzzle->post($url, [
                 'headers' => $headers,
                 'body' => $json,
             ]);
@@ -145,11 +146,11 @@ public function downloadContents($url, $fileHandler = null)
         if ($fileHandler === null) {
             $fileHandler = tmpfile();
         }
-        $stream = \GuzzleHttp\Psr7\stream_for($fileHandler);
+        $stream = Stream::factory($fileHandler);
 
         try {
-            $res = $this->guzzle->request('GET', $url, [
-                'sink' => $stream,
+            $res = $this->guzzle->get($url, [
+                'save_to' => $stream,
                 'headers' => $this->credentials(),
             ]);
         } catch (BadResponseException $e) {
diff --git a/tests/LINEBot/GettingContentsTest.php b/tests/LINEBot/GettingContentsTest.php
index b31f11a7..0f82c4fa 100644
--- a/tests/LINEBot/GettingContentsTest.php
+++ b/tests/LINEBot/GettingContentsTest.php
@@ -16,58 +16,66 @@
  */
 namespace LINE\Tests\LINEBot;
 
-use GuzzleHttp\Handler\MockHandler;
-use GuzzleHttp\HandlerStack;
-use GuzzleHttp\Psr7\Request;
-use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Event\Emitter;
+use GuzzleHttp\Message\Request;
+use GuzzleHttp\Message\Response;
+use GuzzleHttp\Stream\Stream;
+use GuzzleHttp\Subscriber\History;
+use GuzzleHttp\Subscriber\Mock;
 use LINE\LINEBot;
 
 class GettingContentsTest extends \PHPUnit_Framework_TestCase
 {
     public function testGetUserProfile()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'GET');
-                $this->assertEquals(
-                    $req->getUri(),
-                    'https://trialbot-api.line.me/v1/profiles?mids=DUMMY_MID_GET_DISPLAY_NAME'
-                );
-
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"start":1,"display":1,"total":1,"count":1,"contacts":[{"displayName":"BOT API","mid":"u0047556f2e40dba2456887320ba7c76d","pictureUrl":"http://example.com/abcdefghijklmn","statusMessage":"Hello, LINE!"}]}'
-                );
-            },
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"start":1,"display":1,"total":1,"count":1,"contacts":[{"displayName":"BOT API","mid":"u0047556f2e40dba2456887320ba7c76d","pictureUrl":"http://example.com/abcdefghijklmn","statusMessage":"Hello, LINE!"}]}')
+            ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
 
         $config = [
             'channelId' => '1000000000',
             'channelSecret' => 'testsecret',
             'channelMid' => 'TEST_MID',
         ];
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
+
         $sdk = new LINEBot(
             $config,
-            new LINEBot\HTTPClient\GuzzleHTTPClient(array_merge($config, ['handler' => $mockHandler]))
+            new LINEBot\HTTPClient\GuzzleHTTPClient(array_merge($config, ['emitter' => $emitter]))
         );
 
         $res = $sdk->getUserProfile('DUMMY_MID_GET_DISPLAY_NAME');
         $this->assertEquals($res['count'], 1);
         $this->assertEquals($res['contacts'][0]['displayName'], 'BOT API');
+
+        $history = $histories->getIterator()[0];
+
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'GET');
+        $this->assertEquals(
+            $req->getUrl(),
+            'https://trialbot-api.line.me/v1/profiles?mids=DUMMY_MID_GET_DISPLAY_NAME'
+        );
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
     }
 }
diff --git a/tests/LINEBot/MessageSendingTest.php b/tests/LINEBot/MessageSendingTest.php
index 0d862735..de2e9a8e 100644
--- a/tests/LINEBot/MessageSendingTest.php
+++ b/tests/LINEBot/MessageSendingTest.php
@@ -16,10 +16,12 @@
  */
 namespace LINE\Tests\LINEBot;
 
-use GuzzleHttp\Handler\MockHandler;
-use GuzzleHttp\HandlerStack;
-use GuzzleHttp\Psr7\Request;
-use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Event\Emitter;
+use GuzzleHttp\Message\Request;
+use GuzzleHttp\Message\Response;
+use GuzzleHttp\Stream\Stream;
+use GuzzleHttp\Subscriber\History;
+use GuzzleHttp\Subscriber\Mock;
 use LINE\LINEBot;
 use LINE\LINEBot\Constant\ContentType;
 use LINE\LINEBot\Constant\RecipientType;
@@ -35,48 +37,34 @@ class MessageSendingTest extends \PHPUnit_Framework_TestCase
 
     public function testSendText()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 138311608800106203);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-                $this->assertEquals($data['content']['text'], 'hello!');
-                $this->assertEquals($data['content']['contentType'], ContentType::TEXT);
-                $this->assertEquals($data['content']['toType'], RecipientType::USER);
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460826285060","timestamp":1460826285060,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460826285060","timestamp":1460826285060,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')
+            ),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory(
+                    '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                )
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $res = $sdk->sendText(['DUMMY_MID'], 'hello!');
@@ -104,53 +92,63 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
+
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 138311608800106203);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+        $this->assertEquals($data['content']['text'], 'hello!');
+        $this->assertEquals($data['content']['contentType'], ContentType::TEXT);
+        $this->assertEquals($data['content']['toType'], RecipientType::USER);
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
+
     }
 
     public function testSendImage()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 138311608800106203);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-                $this->assertEquals($data['content']['originalContentUrl'], 'http://example.com/image.jpg');
-                $this->assertEquals($data['content']['previewImageUrl'], 'http://example.com/preview.jpg');
-                $this->assertEquals($data['content']['contentType'], ContentType::IMAGE);
-                $this->assertEquals($data['content']['toType'], RecipientType::USER);
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460826285060","timestamp":1460826285060,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460826285060","timestamp":1460826285060,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory(
+                    '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                )
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $res = $sdk->sendImage(['DUMMY_MID'], 'http://example.com/image.jpg', 'http://example.com/preview.jpg');
@@ -178,53 +176,64 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
+
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 138311608800106203);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+        $this->assertEquals($data['content']['originalContentUrl'], 'http://example.com/image.jpg');
+        $this->assertEquals($data['content']['previewImageUrl'], 'http://example.com/preview.jpg');
+        $this->assertEquals($data['content']['contentType'], ContentType::IMAGE);
+        $this->assertEquals($data['content']['toType'], RecipientType::USER);
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
     }
 
     public function testSendVideo()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 138311608800106203);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-                $this->assertEquals($data['content']['originalContentUrl'], 'http://example.com/video.mp4');
-                $this->assertEquals($data['content']['previewImageUrl'], 'http://example.com/preview.jpg');
-                $this->assertEquals($data['content']['contentType'], ContentType::VIDEO);
-                $this->assertEquals($data['content']['toType'], RecipientType::USER);
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')
+            ),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory(
+                    '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                )
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $res = $sdk->sendVideo(['DUMMY_MID'], 'http://example.com/video.mp4', 'http://example.com/preview.jpg');
@@ -252,53 +261,64 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
+
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 138311608800106203);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+        $this->assertEquals($data['content']['originalContentUrl'], 'http://example.com/video.mp4');
+        $this->assertEquals($data['content']['previewImageUrl'], 'http://example.com/preview.jpg');
+        $this->assertEquals($data['content']['contentType'], ContentType::VIDEO);
+        $this->assertEquals($data['content']['toType'], RecipientType::USER);
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
     }
 
     public function testSendAudio()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 138311608800106203);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-                $this->assertEquals($data['content']['originalContentUrl'], 'http://example.com/sound.m4a');
-                $this->assertEquals($data['content']['contentMetadata']['AUDLEN'], '5000');
-                $this->assertEquals($data['content']['contentType'], ContentType::AUDIO);
-                $this->assertEquals($data['content']['toType'], RecipientType::USER);
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')
+            ),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory(
+                    '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                )
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $res = $sdk->sendAudio(['DUMMY_MID'], 'http://example.com/sound.m4a', 5000);
@@ -326,58 +346,61 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
+
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 138311608800106203);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+        $this->assertEquals($data['content']['originalContentUrl'], 'http://example.com/sound.m4a');
+        $this->assertEquals($data['content']['contentMetadata']['AUDLEN'], '5000');
+        $this->assertEquals($data['content']['contentType'], ContentType::AUDIO);
+        $this->assertEquals($data['content']['toType'], RecipientType::USER);
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
     }
 
     public function testSendLocation()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 138311608800106203);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-
-                $content = $data['content'];
-                $location = $content['location'];
-
-                $this->assertEquals($content['contentType'], ContentType::LOCATION);
-                $this->assertEquals($content['text'], '2 Chome-21-1 Shibuya Tokyo 150-0002, Japan');
-                $this->assertEquals($location['title'], $content['text']);
-                $this->assertEquals($location['latitude'], 35.658240);
-                $this->assertEquals($location['longitude'], 139.703478);
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory('{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}')
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $res = $sdk->sendLocation(['DUMMY_MID'], '2 Chome-21-1 Shibuya Tokyo 150-0002, Japan', 35.658240, 139.703478);
@@ -405,54 +428,69 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
+
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 138311608800106203);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+
+        $content = $data['content'];
+        $location = $content['location'];
+
+        $this->assertEquals($content['contentType'], ContentType::LOCATION);
+        $this->assertEquals($content['text'], '2 Chome-21-1 Shibuya Tokyo 150-0002, Japan');
+        $this->assertEquals($location['title'], $content['text']);
+        $this->assertEquals($location['latitude'], 35.658240);
+        $this->assertEquals($location['longitude'], 139.703478);
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
     }
 
     public function testSendSticker()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 138311608800106203);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-
-                $this->assertEquals($data['content']['contentType'], ContentType::STICKER);
-                $this->assertEquals($data['content']['contentMetadata']['STKID'], '1');
-                $this->assertEquals($data['content']['contentMetadata']['STKPKGID'], '2');
-                $this->assertEquals($data['content']['contentMetadata']['STKVER'], '100');
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')
+            ),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory(
+                    '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                )
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $res = $sdk->sendSticker(['DUMMY_MID'], 1, 2, 100);
@@ -480,5 +518,32 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
+
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 138311608800106203);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+
+        $this->assertEquals($data['content']['contentType'], ContentType::STICKER);
+        $this->assertEquals($data['content']['contentMetadata']['STKID'], '1');
+        $this->assertEquals($data['content']['contentMetadata']['STKPKGID'], '2');
+        $this->assertEquals($data['content']['contentMetadata']['STKVER'], '100');
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
     }
 }
\ No newline at end of file
diff --git a/tests/LINEBot/MultipleMessagesSendingTest.php b/tests/LINEBot/MultipleMessagesSendingTest.php
index 266e43cc..12387244 100644
--- a/tests/LINEBot/MultipleMessagesSendingTest.php
+++ b/tests/LINEBot/MultipleMessagesSendingTest.php
@@ -16,10 +16,12 @@
  */
 namespace LINE\Tests\LINEBot;
 
-use GuzzleHttp\Handler\MockHandler;
-use GuzzleHttp\HandlerStack;
-use GuzzleHttp\Psr7\Request;
-use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Event\Emitter;
+use GuzzleHttp\Message\Request;
+use GuzzleHttp\Message\Response;
+use GuzzleHttp\Stream\Stream;
+use GuzzleHttp\Subscriber\History;
+use GuzzleHttp\Subscriber\Mock;
 use LINE\LINEBot;
 use LINE\LINEBot\Constant\ContentType;
 use LINE\LINEBot\HTTPClient\GuzzleHTTPClient;
@@ -29,90 +31,38 @@ class MultipleMessagesSendingTest extends \PHPUnit_Framework_TestCase
 {
     public function testMultipleMessages()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 140177271400161403);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-
-                $this->assertEquals(sizeof($data['content']['messages']), 6);
-
-                {
-                    $content = $data['content']['messages'][0];
-                    $this->assertEquals($content['text'], 'hello!');
-                    $this->assertEquals($content['contentType'], ContentType::TEXT);
-                }
-                {
-                    $content = $data['content']['messages'][1];
-                    $this->assertEquals($content['originalContentUrl'], 'http://example.com/image.jpg');
-                    $this->assertEquals($content['previewImageUrl'], 'http://example.com/preview.jpg');
-                    $this->assertEquals($content['contentType'], ContentType::IMAGE);
-                }
-                {
-                    $content = $data['content']['messages'][2];
-                    $this->assertEquals($content['originalContentUrl'], 'http://example.com/audio.m4a');
-                    $this->assertEquals($content['contentMetadata']['AUDLEN'], '6000');
-                    $this->assertEquals($content['contentType'], ContentType::AUDIO);
-                }
-                {
-                    $content = $data['content']['messages'][3];
-                    $this->assertEquals($content['originalContentUrl'], 'http://example.com/video.mp4');
-                    $this->assertEquals($content['previewImageUrl'], 'http://example.com/video_preview.jpg');
-                    $this->assertEquals($content['contentType'], ContentType::VIDEO);
-                }
-                {
-                    $content = $data['content']['messages'][4];
-                    $location = $content['location'];
-                    $this->assertEquals($content['text'], '2 Chome-21-1 Shibuya Tokyo 150-0002, Japan');
-                    $this->assertEquals($location['title'], $content['text']);
-                    $this->assertEquals($location['latitude'], 35.658240);
-                    $this->assertEquals($location['longitude'], 139.703478);
-                    $this->assertEquals($content['contentType'], ContentType::LOCATION);
-                }
-                {
-                    $content = $data['content']['messages'][5];
-                    $this->assertEquals($content['contentType'], ContentType::STICKER);
-                    $this->assertEquals($content['contentMetadata']['STKID'], '1');
-                    $this->assertEquals($content['contentMetadata']['STKPKGID'], '2');
-                    $this->assertEquals($content['contentMetadata']['STKVER'], '100');
-                }
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')
+            ),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory(
+                    '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                )
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
 
         $config = [
             'channelId' => '1000000000',
             'channelSecret' => 'testsecret',
             'channelMid' => 'TEST_MID',
         ];
-        $sdk = new LINEBot($config, new GuzzleHTTPClient(array_merge($config, ['handler' => $mockHandler])));
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
+
+        $sdk = new LINEBot($config, new GuzzleHTTPClient(array_merge($config, ['emitter' => $emitter])));
 
         $multipleMessages = (new MultipleMessages())
             ->addText('hello!')
@@ -147,6 +97,69 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
-    }
 
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 140177271400161403);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+
+        $this->assertEquals(sizeof($data['content']['messages']), 6);
+
+        {
+            $content = $data['content']['messages'][0];
+            $this->assertEquals($content['text'], 'hello!');
+            $this->assertEquals($content['contentType'], ContentType::TEXT);
+        }
+        {
+            $content = $data['content']['messages'][1];
+            $this->assertEquals($content['originalContentUrl'], 'http://example.com/image.jpg');
+            $this->assertEquals($content['previewImageUrl'], 'http://example.com/preview.jpg');
+            $this->assertEquals($content['contentType'], ContentType::IMAGE);
+        }
+        {
+            $content = $data['content']['messages'][2];
+            $this->assertEquals($content['originalContentUrl'], 'http://example.com/audio.m4a');
+            $this->assertEquals($content['contentMetadata']['AUDLEN'], '6000');
+            $this->assertEquals($content['contentType'], ContentType::AUDIO);
+        }
+        {
+            $content = $data['content']['messages'][3];
+            $this->assertEquals($content['originalContentUrl'], 'http://example.com/video.mp4');
+            $this->assertEquals($content['previewImageUrl'], 'http://example.com/video_preview.jpg');
+            $this->assertEquals($content['contentType'], ContentType::VIDEO);
+        }
+        {
+            $content = $data['content']['messages'][4];
+            $location = $content['location'];
+            $this->assertEquals($content['text'], '2 Chome-21-1 Shibuya Tokyo 150-0002, Japan');
+            $this->assertEquals($location['title'], $content['text']);
+            $this->assertEquals($location['latitude'], 35.658240);
+            $this->assertEquals($location['longitude'], 139.703478);
+            $this->assertEquals($content['contentType'], ContentType::LOCATION);
+        }
+        {
+            $content = $data['content']['messages'][5];
+            $this->assertEquals($content['contentType'], ContentType::STICKER);
+            $this->assertEquals($content['contentMetadata']['STKID'], '1');
+            $this->assertEquals($content['contentMetadata']['STKPKGID'], '2');
+            $this->assertEquals($content['contentMetadata']['STKVER'], '100');
+        }
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
+    }
 }
\ No newline at end of file
diff --git a/tests/LINEBot/RichMessageSendingTest.php b/tests/LINEBot/RichMessageSendingTest.php
index 65191c7c..90cb62fb 100644
--- a/tests/LINEBot/RichMessageSendingTest.php
+++ b/tests/LINEBot/RichMessageSendingTest.php
@@ -16,10 +16,13 @@
  */
 namespace LINE\Tests\LINEBot;
 
-use GuzzleHttp\Handler\MockHandler;
-use GuzzleHttp\HandlerStack;
-use GuzzleHttp\Psr7\Request;
-use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Client;
+use GuzzleHttp\Event\Emitter;
+use GuzzleHttp\Message\Request;
+use GuzzleHttp\Message\Response;
+use GuzzleHttp\Stream\Stream;
+use GuzzleHttp\Subscriber\History;
+use GuzzleHttp\Subscriber\Mock;
 use LINE\LINEBot;
 use LINE\LINEBot\HTTPClient\GuzzleHTTPClient;
 use LINE\LINEBot\Message\RichMessage\Markup;
@@ -28,107 +31,38 @@ class RichMessageSendingTest extends \PHPUnit_Framework_TestCase
 {
     public function testRichMessage()
     {
-        $mock = new MockHandler([
-            function (Request $req) {
-                $this->assertEquals($req->getMethod(), 'POST');
-                $this->assertEquals($req->getUri(), 'https://trialbot-api.line.me/v1/events');
-
-                $data = json_decode($req->getBody(), true);
-                $this->assertEquals($data['eventType'], 138311608800106203);
-                $this->assertEquals($data['to'], ['DUMMY_MID']);
-                $this->assertEquals($data['content']['contentMetadata']['ALT_TEXT'], 'Alt text');
-                $this->assertEquals(
-                    $data['content']['contentMetadata']['DOWNLOAD_URL'],
-                    'http://example.com/image.jpg'
-                );
-
-                $json = $data['content']['contentMetadata']['MARKUP_JSON'];
-                $this->assertEquals(
-                    json_decode($json, true),
-                    [
-                        'scenes' => [
-                            'scene1' => [
-                                'listeners' => [
-                                    [
-                                        'params' => [
-                                            0,
-                                            0,
-                                            520,
-                                            520,
-                                        ],
-                                        'type' => 'touch',
-                                        'action' => 'SOMETHING',
-                                    ],
-                                ],
-                                'draws' => [
-                                    [
-                                        'image' => 'image1',
-                                        'x' => 0,
-                                        'y' => 0,
-                                        'w' => 1040,
-                                        'h' => 1040,
-                                    ],
-                                ],
-                            ],
-                        ],
-                        'images' => [
-                            'image1' => [
-                                'x' => 0,
-                                'y' => 0,
-                                'w' => 1040,
-                                'h' => 1040,
-                            ],
-                        ],
-                        'actions' => [
-                            'SOMETHING' => [
-                                'text' => 'something',
-                                'params' => [
-                                    'linkUri' => 'https://line.me',
-                                ],
-                                'type' => 'web',
-                            ],
-                        ],
-                        'canvas' => [
-                            'initialScene' => 'scene1',
-                            'width' => 1040,
-                            'height' => 1040,
-                        ],
-                    ]
-                );
-
-                $channelIdHeader = $req->getHeader('X-Line-ChannelID');
-                $this->assertEquals(sizeof($channelIdHeader), 1);
-                $this->assertEquals($channelIdHeader[0], '1000000000');
-
-                $channelSecretHeader = $req->getHeader('X-Line-ChannelSecret');
-                $this->assertEquals(sizeof($channelSecretHeader), 1);
-                $this->assertEquals($channelSecretHeader[0], 'testsecret');
-
-                $channelMidHeader = $req->getHeader('X-Line-Trusted-User-With-ACL');
-                $this->assertEquals(sizeof($channelMidHeader), 1);
-                $this->assertEquals($channelMidHeader[0], 'TEST_MID');
-
-                return new Response(
-                    200,
-                    [],
-                    '{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}'
-                );
-            },
-            new Response(400, [], '{"statusCode":"422","statusMessage":"invalid users"}'),
+        $mock = new Mock([
+            new Response(
+                200,
+                [],
+                Stream::factory('{"failed":[],"messageId":"1460867315795","timestamp":1460867315795,"version":1}')
+            ),
+            new Response(
+                400,
+                [],
+                Stream::factory('{"statusCode":"422","statusMessage":"invalid users"}')
+            ),
             new Response(
                 500,
                 [],
-                '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                Stream::factory(
+                    '{"statusCode":"500","statusMessage":"unexpected error found at call bot api sendMessage"}'
+                )
             ),
         ]);
-        $mockHandler = HandlerStack::create($mock);
 
         $config = [
             'channelId' => '1000000000',
             'channelSecret' => 'testsecret',
             'channelMid' => 'TEST_MID',
         ];
-        $sdk = new LINEBot($config, new GuzzleHTTPClient(array_merge($config, ['handler' => $mockHandler])));
+
+        $histories = new History();
+        $emitter = new Emitter();
+        $emitter->attach($mock);
+        $emitter->attach($histories);
+
+        $sdk = new LINEBot($config, new GuzzleHTTPClient(array_merge($config, ['emitter' => $emitter])));
 
         $markup = (new Markup(1040))
             ->setAction('SOMETHING', 'something', 'https://line.me')
@@ -159,5 +93,87 @@ function (Request $req) {
         $this->assertEquals(500, $res->getHTTPStatus());
         $this->assertEquals('500', $res->getStatusCode());
         $this->assertEquals('unexpected error found at call bot api sendMessage', $res->getStatusMessage());
+
+        $history = $histories->getIterator()[0];
+        /** @var Request $req */
+        $req = $history['request'];
+
+        $this->assertEquals($req->getMethod(), 'POST');
+        $this->assertEquals($req->getUrl(), 'https://trialbot-api.line.me/v1/events');
+
+        $data = json_decode($req->getBody(), true);
+        $this->assertEquals($data['eventType'], 138311608800106203);
+        $this->assertEquals($data['to'], ['DUMMY_MID']);
+        $this->assertEquals($data['content']['contentMetadata']['ALT_TEXT'], 'Alt text');
+        $this->assertEquals(
+            $data['content']['contentMetadata']['DOWNLOAD_URL'],
+            'http://example.com/image.jpg'
+        );
+
+        $json = $data['content']['contentMetadata']['MARKUP_JSON'];
+        $this->assertEquals(
+            json_decode($json, true),
+            [
+                'scenes' => [
+                    'scene1' => [
+                        'listeners' => [
+                            [
+                                'params' => [
+                                    0,
+                                    0,
+                                    520,
+                                    520,
+                                ],
+                                'type' => 'touch',
+                                'action' => 'SOMETHING',
+                            ],
+                        ],
+                        'draws' => [
+                            [
+                                'image' => 'image1',
+                                'x' => 0,
+                                'y' => 0,
+                                'w' => 1040,
+                                'h' => 1040,
+                            ],
+                        ],
+                    ],
+                ],
+                'images' => [
+                    'image1' => [
+                        'x' => 0,
+                        'y' => 0,
+                        'w' => 1040,
+                        'h' => 1040,
+                    ],
+                ],
+                'actions' => [
+                    'SOMETHING' => [
+                        'text' => 'something',
+                        'params' => [
+                            'linkUri' => 'https://line.me',
+                        ],
+                        'type' => 'web',
+                    ],
+                ],
+                'canvas' => [
+                    'initialScene' => 'scene1',
+                    'width' => 1040,
+                    'height' => 1040,
+                ],
+            ]
+        );
+
+        $channelIdHeader = $req->getHeaderAsArray('X-Line-ChannelID');
+        $this->assertEquals(sizeof($channelIdHeader), 1);
+        $this->assertEquals($channelIdHeader[0], '1000000000');
+
+        $channelSecretHeader = $req->getHeaderAsArray('X-Line-ChannelSecret');
+        $this->assertEquals(sizeof($channelSecretHeader), 1);
+        $this->assertEquals($channelSecretHeader[0], 'testsecret');
+
+        $channelMidHeader = $req->getHeaderAsArray('X-Line-Trusted-User-With-ACL');
+        $this->assertEquals(sizeof($channelMidHeader), 1);
+        $this->assertEquals($channelMidHeader[0], 'TEST_MID');
     }
 }
\ No newline at end of file
diff --git a/tests/LINEBotTest.php b/tests/LINEBotTest.php
index e474c8f4..73ecca47 100644
--- a/tests/LINEBotTest.php
+++ b/tests/LINEBotTest.php
@@ -16,9 +16,10 @@
  */
 namespace LINE\Tests;
 
-use GuzzleHttp\Handler\MockHandler;
-use GuzzleHttp\HandlerStack;
-use GuzzleHttp\Psr7\Response;
+use GuzzleHttp\Event\Emitter;
+use GuzzleHttp\Message\Response;
+use GuzzleHttp\Stream\Stream;
+use GuzzleHttp\Subscriber\Mock;
 use LINE\LINEBot;
 use LINE\LINEBot\HTTPClient\GuzzleHTTPClient;
 
@@ -35,14 +36,16 @@ class LINEBotTest extends \PHPUnit_Framework_TestCase
      */
     public function testLINEBotAPIExceptionCausedByEmptyResponseBody()
     {
-        $mock = new MockHandler([
+        $mock = new Mock([
             new Response(200, []), // missing body
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $emitter = new Emitter();
+        $emitter->attach($mock);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $sdk->sendText(['DUMMY_MID'], 'hello!');
@@ -53,14 +56,16 @@ public function testLINEBotAPIExceptionCausedByEmptyResponseBody()
      */
     public function textLINEBotAPIExceptionCausedByInvalidResponseBody()
     {
-        $mock = new MockHandler([
-            new Response(200, [], 'I AM NOT A JSON'), // not JSON
+        $mock = new Mock([
+            new Response(200, [], Stream::factory('I AM NOT A JSON')), // not JSON
         ]);
-        $mockHandler = HandlerStack::create($mock);
+
+        $emitter = new Emitter();
+        $emitter->attach($mock);
 
         $sdk = new LINEBot(
             $this::$config,
-            new GuzzleHTTPClient(array_merge($this::$config, ['handler' => $mockHandler]))
+            new GuzzleHTTPClient(array_merge($this::$config, ['emitter' => $emitter]))
         );
 
         $sdk->sendText(['DUMMY_MID'], 'hello!');