diff --git a/composer.json b/composer.json
index b95cfc0..eb3a059 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
     "PHP": ">=7.1"
   },
   "require-dev": {
-    "phpunit/phpunit": "^6.0",
+    "phpunit/phpunit": "^9.5",
     "friendsofphp/php-cs-fixer": "^3.0",
     "phpstan/phpstan": "^1.0"
   },