diff --git a/composer.json b/composer.json
index b6b8606..affc86d 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
     "php": "^7.1.0 || ^8.0",
     "ext-mongodb": "*",
     "mongodb/mongodb": "^1.0",
-    "phpunit/phpunit": ">=6.0,<10.0",
+    "phpunit/phpunit": ">=6.0,<12.0",
     "ext-json": "*"
   },
   "autoload": {