diff --git a/composer.json b/composer.json
index 3a78973..b34dc32 100644
--- a/composer.json
+++ b/composer.json
@@ -40,5 +40,8 @@
     "allow-plugins": {
       "topfloor/composer-cleanup-vcs-dirs": false
     }
+  },
+  "require-dev": {
+    "phpunit/phpunit": "^10.0"
   }
 }