diff --git a/composer.json b/composer.json
index f53f67c..334f290 100644
--- a/composer.json
+++ b/composer.json
@@ -26,7 +26,7 @@
     },
     "require-dev": {
         "react-parallel/pool-tests": "^4.0.0",
-        "wyrihaximus/async-test-utilities": "^7.2"
+        "wyrihaximus/async-test-utilities": "^7.2 || ^9.0"
     },
     "autoload": {
         "psr-4": {