diff --git a/composer.json b/composer.json
index 0e933e3..dc80ed1 100644
--- a/composer.json
+++ b/composer.json
@@ -7,7 +7,7 @@
         "php": ">=5.6"
     },
     "require-dev": {
-        "phpunit/phpunit": "5.7.25"
+        "phpunit/phpunit": "5.7.*"
     },
     "license": "MIT",
     "authors": [