diff --git a/Email/AbstractEmailType.php b/Email/AbstractEmailType.php
index d169aef..0a4cb9c 100644
--- a/Email/AbstractEmailType.php
+++ b/Email/AbstractEmailType.php
@@ -13,7 +13,7 @@ abstract class AbstractEmailType implements EmailTypeInterface
     /**
      * {@inheritdoc}
      */
-    abstract public function buildMessage(\Swift_Mime_Message $message, array $parameters);
+    abstract public function buildMessage(\Swift_Message $message, array $parameters);
 
     /**
      * @param EngineInterface $templating
diff --git a/Email/EmailTypeInterface.php b/Email/EmailTypeInterface.php
index 723cfae..1fb7b39 100644
--- a/Email/EmailTypeInterface.php
+++ b/Email/EmailTypeInterface.php
@@ -18,10 +18,10 @@ interface EmailTypeInterface
     /**
      * Builds message instance
      *
-     * @param \Swift_Mime_Message $message
+     * @param \Swift_Message $message
      * @return mixed
      */
-    public function buildMessage(\Swift_Mime_Message $message, array $parameters);
+    public function buildMessage(\Swift_Message $message, array $parameters);
 
     /**
      * Set's templating engine
diff --git a/Email/TemplateType.php b/Email/TemplateType.php
index 3d237dd..b4fd42c 100644
--- a/Email/TemplateType.php
+++ b/Email/TemplateType.php
@@ -57,7 +57,7 @@ protected function setTemplateVariable($key, $value)
     /**
      * {@inheritdoc}
      */
-    public function buildMessage(\Swift_Mime_Message $message, array $parameters)
+    public function buildMessage(\Swift_Message $message, array $parameters)
     {
         if ($this->subject instanceof TranslatableString) {
             $this->subject = $this->subject->getString($this->getTranslator());
diff --git a/Service/EmailSender.php b/Service/EmailSender.php
index 011f013..be12a5c 100644
--- a/Service/EmailSender.php
+++ b/Service/EmailSender.php
@@ -39,10 +39,10 @@ public function addParameter($key, $value)
         $this->parameters[$key] = $value;
     }
 
-    public function buildMessage(EmailTypeInterface $type, \Swift_Mime_Message $message = null)
+    public function buildMessage(EmailTypeInterface $type, \Swift_Message $message = null)
     {
         if (null === $message) {
-            $message = \Swift_Message::newInstance();
+            $message =  new \Swift_Message();
         }
 
         $type->setTemplating($this->templating);
@@ -52,7 +52,7 @@ public function buildMessage(EmailTypeInterface $type, \Swift_Mime_Message $mess
         return $message;
     }
 
-    public function sendMessage(\Swift_Mime_Message $message)
+    public function sendMessage(\Swift_Message $message)
     {
         return $this->mailer->send($message);
     }
diff --git a/composer.json b/composer.json
index b1407f3..4f92305 100644
--- a/composer.json
+++ b/composer.json
@@ -11,10 +11,10 @@
         }
     ],
     "require": {
-        "swiftmailer/swiftmailer": "^4.2 || ^5.0",
-        "symfony/framework-bundle": "^2.3 || ^3.0",
-        "symfony/dependency-injection": "^3.1",
-        "symfony/yaml": "^2.3 || ^3.0"
+        "swiftmailer/swiftmailer": "^4.2 || ^6.0",
+        "symfony/framework-bundle": "^3.0 || ^4.1",
+        "symfony/dependency-injection": "^3.1 || ^4.1",
+        "symfony/yaml": "^3.0 || ^4.1"
     },
     "autoload": {
         "psr-4": {