diff --git a/composer.json b/composer.json
index 9ec9b44..b35b959 100644
--- a/composer.json
+++ b/composer.json
@@ -7,7 +7,7 @@
         "doctrine/inflector": "^1.0"
     },
     "require-dev": {
-        "gecko-packages/gecko-php-unit": "^2.0",
+        "gecko-packages/gecko-php-unit": "^2.0 || ^3.0",
         "phpunit/phpunit": "^6.0",
         "friendsofphp/php-cs-fixer": "2.14.2"
     },