diff --git a/composer.json b/composer.json
index 83cd856..0ca72b1 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
     "description": "Php HTTP client library for Classy API",
     "version": "1.2.0",
     "require": {
-        "guzzlehttp/guzzle": "^6.2"
+        "guzzlehttp/guzzle": "^7.0"
     },
     "require-dev": {
         "phpunit/phpunit": "~4.0",
diff --git a/src/Session.php b/src/Session.php
index d8a3700..5bf3016 100644
--- a/src/Session.php
+++ b/src/Session.php
@@ -5,7 +5,7 @@
 use Classy\Exceptions\SDKException;
 use DateTime;
 
-Class Session implements \Serializable
+Class Session
 {
     /**
      * @var string
@@ -108,4 +108,12 @@ public function unserialize($serialized)
             $this->$key = $value;
         }
     }
+
+    public function __serialize() {
+        return $this->serialize(get_object_vars($this));
+    }
+
+    public function __unserialize(array $data): void {
+        $this->unserialize($data);
+    }
 }