diff --git a/composer.json b/composer.json
index 6928359..195af0c 100644
--- a/composer.json
+++ b/composer.json
@@ -29,7 +29,7 @@
     "sebastiankrupinski/jmap-client-php": "dev-main"
   },
   "require-dev": {
-    "phpunit/phpunit": "^11.0"
+    "phpunit/phpunit": "^13.0"
   },
   "autoload": {
     "psr-4": {