diff --git a/composer.json b/composer.json
index 1be282c..403ec0f 100644
--- a/composer.json
+++ b/composer.json
@@ -26,7 +26,7 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "^8.5.14",
+        "phpunit/phpunit": "^8.5.14 || ^9.0.0",
         "phpstan/phpstan": "0.12.81",
         "diablomedia/zendframework1-view-helper-layout": "^1.0",
         "friendsofphp/php-cs-fixer": "2.18.3",