diff --git a/composer.json b/composer.json
index 2213aa7..5961754 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
         "mustache/mustache": "~2.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.3",
+        "phpunit/phpunit": "^8.5.52",
         "satooshi/php-coveralls": "^2.0"
     },
     "autoload": {