diff --git a/src/Controller/MailmuteController.php b/src/Controller/MailmuteController.php
index bc832f9..cb25366 100644
--- a/src/Controller/MailmuteController.php
+++ b/src/Controller/MailmuteController.php
@@ -7,6 +7,7 @@
 namespace Drupal\mailmute\Controller;
 
 use Drupal\Core\Controller\ControllerBase;
+use Drupal\Core\Render\RendererInterface;
 use Drupal\mailmute\SendStateManagerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
@@ -23,17 +24,28 @@ class MailmuteController extends ControllerBase {
   protected $manager;
 
   /**
+   * The renderer service.
+   *
+   * @var \Drupal\Core\Render\RendererInterface
+   */
+  protected $renderer;
+
+  /**
    * Creates a new Mailmute controller.
    */
-  public function __construct(SendStateManagerInterface $manager) {
+  public function __construct(SendStateManagerInterface $manager, RendererInterface $renderer) {
     $this->manager = $manager;
+    $this->renderer = $renderer;
   }
 
   /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container) {
-    return new static($container->get('plugin.manager.sendstate'));
+    return new static(
+      $container->get('plugin.manager.sendstate'),
+      $container->get('renderer')
+    );
   }
 
   /**
@@ -59,7 +71,7 @@ class MailmuteController extends ControllerBase {
         '#size' => $level,
       );
       $build['states'][] = array(
-        'label' => array('#markup' => drupal_render($indentation) . $definition['label']),
+        'label' => array('#markup' => $this->renderer->render($indentation) . $definition['label']),
         'module' => array('#markup' => $definition['provider']),
         'description' => array('#markup' => $definition['description']),
         'muting' => array('#markup' => $definition['mute'] ? $this->t('Yes') : $this->t('No')),