diff --git a/app/workers/mails.php b/app/workers/mails.php
index 1ea82eec30..e80759cead 100644
--- a/app/workers/mails.php
+++ b/app/workers/mails.php
@@ -15,7 +15,7 @@ class MailsV1
      */
     public $args = [];
 
-    public function setUp()
+    public function setUp(): void
     {
     }
 
@@ -63,7 +63,7 @@ class MailsV1
         }
     }
 
-    public function tearDown()
+    public function tearDown(): void
     {
         // ... Remove environment for this job
     }