diff --git a/.travis.yml b/.travis.yml
index 1dfbb818..82479e7a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,6 @@
 language: php
 php:
-  - 5.6
+  - 7.3
 notifications:
   email:
     recipients:
diff --git a/composer.json b/composer.json
index 6eecca14..f9087db1 100644
--- a/composer.json
+++ b/composer.json
@@ -21,8 +21,8 @@
      }
     },
     "require": {
-        "php": ">=5.3.0",
-        "guzzlehttp/guzzle": "~6.3",
-        "guzzlehttp/guzzle-services": "~1.1"
+        "php": ">=7.3",
+        "guzzlehttp/guzzle": "^7.0.1",
+        "guzzlehttp/guzzle-services": "~1.2"
     }
 }
diff --git a/src/Qcloud/Cos/Client.php b/src/Qcloud/Cos/Client.php
index 77d94bc6..0f3d3f2f 100644
--- a/src/Qcloud/Cos/Client.php
+++ b/src/Qcloud/Cos/Client.php
@@ -75,7 +75,7 @@
  * @method object SelectObjectContent (array $arg)
  */
 class Client extends GuzzleClient {
-    const VERSION = '2.1.2';
+    const VERSION = '3.0.0';
 
     public $httpClient;
     
@@ -212,7 +212,7 @@ public function getObjectUrl($bucket, $key, $expires = "+30 minutes", array $arg
     }
 
     public function upload($bucket, $key, $body, $options = array()) {
-        $body = Psr7\stream_for($body);
+        $body = Psr7\Utils::streamFor($body);
         $options['PartSize'] = isset($options['PartSize']) ? $options['PartSize'] : MultipartUpload::DEFAULT_PART_SIZE;
         if ($body->getSize() < $options['PartSize']) {
             $rt = $this->putObject(array(
@@ -233,7 +233,7 @@ public function upload($bucket, $key, $body, $options = array()) {
     }
 
     public function resumeUpload($bucket, $key, $body, $uploadId, $options = array()) {
-        $body = Psr7\stream_for($body);
+        $body = Psr7\Utils::streamFor($body);
         $options['PartSize'] = isset($options['PartSize']) ? $options['PartSize'] : MultipartUpload::DEFAULT_PART_SIZE;
         $multipartUpload = new MultipartUpload($this, $body, array(
                 'Bucket' => $bucket,
diff --git a/src/Qcloud/Cos/Request/BodyLocation.php b/src/Qcloud/Cos/Request/BodyLocation.php
index 90f97a54..73787fd5 100644
--- a/src/Qcloud/Cos/Request/BodyLocation.php
+++ b/src/Qcloud/Cos/Request/BodyLocation.php
@@ -44,6 +44,6 @@ public function visit(
         }
         // binary string data from bound parameter
         $value = $command[$param->getName()];
-        return $request->withBody(Psr7\stream_for($value));
+        return $request->withBody(Psr7\Utils::streamFor($value));
     }
 }
diff --git a/src/Qcloud/Cos/Tests/COSTest.php b/src/Qcloud/Cos/Tests/COSTest.php
index b02b82f6..3e038202 100644
--- a/src/Qcloud/Cos/Tests/COSTest.php
+++ b/src/Qcloud/Cos/Tests/COSTest.php
@@ -10,8 +10,7 @@ class COSTest extends \PHPUnit\Framework\TestCase
     private $cosClient;
     private $bucket;
     private $region;
-    protected function setUp()
-    {
+    protected function setUp(): void {
         $this->bucket = getenv('COS_BUCKET');
         $this->region = getenv('COS_REGION');
         $this->bucket2 = "tmp".$this->bucket;
@@ -25,7 +24,7 @@ protected function setUp()
         }
     }
 
-    protected function tearDown() {
+    protected function tearDown(): void {
     }
 
     function generateRandomString($length = 10) { 
@@ -718,7 +717,6 @@ public function testGetBucketCorsNull()
                     'Bucket' => $this->bucket
                 )
             );
-            print_r($rt);
             $this->assertTrue(False);
         } catch (ServiceResponseException $e) {
             $this->assertTrue($e->getExceptionCode() === 'NoSuchCORSConfiguration' && $e->getStatusCode() === 404);