diff --git a/lib/Features/FeaturesController.php b/lib/Features/FeaturesController.php
index 71a9da6769..b489c554e0 100644
--- a/lib/Features/FeaturesController.php
+++ b/lib/Features/FeaturesController.php
@@ -7,11 +7,13 @@ class FeaturesController {
   // Define features below in the following form:
   //   const FEATURE_NAME_OF_FEATURE = 'name-of-feature';
   const NEW_DEFAULT_LIST_NAME = 'new-default-list-name';
+  const SEND_WORDPRESS_MAILS_WITH_MP3 = 'send-wordpress-mails-with-mp3';
 
   // Define feature defaults in the array below in the following form:
   //   self::FEATURE_NAME_OF_FEATURE => true,
   private $defaults = [
     self::NEW_DEFAULT_LIST_NAME => false,
+    self::SEND_WORDPRESS_MAILS_WITH_MP3 => false,
   ];
 
   /** @var array */
diff --git a/lib/Mailer/WordPress/WordpressMailerReplacer.php b/lib/Mailer/WordPress/WordpressMailerReplacer.php
index 4c8c1eb0aa..2872cb061b 100644
--- a/lib/Mailer/WordPress/WordpressMailerReplacer.php
+++ b/lib/Mailer/WordPress/WordpressMailerReplacer.php
@@ -2,12 +2,24 @@
 
 namespace MailPoet\Mailer\WordPress;
 
+use MailPoet\Features\FeaturesController;
+
 class WordpressMailerReplacer {
-  
+
+  /** @var FeaturesController */
+  private $features_controller;
+
+  function __construct(FeaturesController $features_controller) {
+    $this->features_controller = $features_controller;
+  }
+
   public function replaceWordPressMailer() {
     global $phpmailer;
 
-    return $this->replaceWithCustomPhpMailer($phpmailer);
+    if ($this->features_controller->isSupported(FeaturesController::SEND_WORDPRESS_MAILS_WITH_MP3)) {
+      return $this->replaceWithCustomPhpMailer($phpmailer);
+    }
+    return $phpmailer;
   }
 
   private function replaceWithCustomPhpMailer(&$obj = null) {