diff --git a/composer.json b/composer.json
index 1879af7..85239c2 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,7 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.5"
+        "phpunit/phpunit": "^9.5 || ^12.0"
     },
     "require": {
         "brick/math": "^0.9.2 || ^0.10.0 || ^0.14.0"