diff --git a/composer.json b/composer.json
index cb6fca40..6d32e09e 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
   "require-dev" : {
-    "phpunit/phpunit" : "5.4.6",
+    "phpunit/phpunit" : "5.7.27",
     "squizlabs/php_codesniffer" : "2.7.1"
   }
 }
\ No newline at end of file