diff --git a/composer.json b/composer.json
index 1ec5626..335c1e4 100644
--- a/composer.json
+++ b/composer.json
@@ -21,6 +21,6 @@
     "netresearch/jsonmapper": "^1.4"
   },
   "require-dev": {
-    "phpunit/phpunit": "^9.0"
+    "phpunit/phpunit": "^13.0"
   }
 }