diff --git a/composer.json b/composer.json
index dd1b781..bdaa07e 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,8 @@
     }
   ],
   "require": {
-    "dompdf/dompdf": "~0.8.0"
+    "dompdf/dompdf": "~0.8.0",
+    "drupal/core": "^8 || ^9"
   },
   "suggest": {
     "mikehaertl/phpwkhtmltopdf": "PhpWkhtmlToPdf provides the PHP library to use Wkhtmltopdf"