diff --git a/composer.json b/composer.json
index 5def396..c4b4f5e 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
   "prefer-stable": true,
   "require": {
     "php": ">=5.6.0",
-    "symfony/yaml": "^3.0",
+    "symfony/yaml": "^4.0",
     "composer/installers": "~1.0"
   },
   "autoload": {