diff --git a/composer.json b/composer.json
index 45c9d57..e3933eb 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,8 @@
 	],
 	"require": {
 		"silverstripe/framework": "~4.0",
-		"silverstripe/vendor-plugin": "^1.0"
+		"silverstripe/vendor-plugin": "^1.0",
+        "phpunit/phpunit": "^9.5"
 	},
 	"require-dev": {
 		"squizlabs/php_codesniffer": "^3"