diff --git a/composer.json b/composer.json
index 2307496a2a..bfe696862b 100644
--- a/composer.json
+++ b/composer.json
@@ -85,7 +85,7 @@
         "php-webdriver/webdriver": "^1.7.1",
         "phpmyadmin/coding-standard": "^1.0",
         "phpstan/phpstan": "^0.11.5",
-        "phpunit/phpunit": "^7.5 || ^8.0",
+        "phpunit/phpunit": "^7.5 || ^8.0 || ^9.0",
         "pragmarx/google2fa-qrcode": "^1.0.1",
         "samyoul/u2f-php-server": "^1.1",
         "squizlabs/php_codesniffer": "^3.0",