diff --git a/composer.json b/composer.json
index 4c325c2..25add6b 100644
--- a/composer.json
+++ b/composer.json
@@ -11,5 +11,8 @@
         "psr-4": {
             "ctiso\\": "src/"
         }
+    },
+    "require": {
+        "phpmailer/phpmailer": "^6.8.0"
     }
 }