diff --git a/composer.json b/composer.json
index 222cad5..a6c09ca 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": ">=5.5",
-        "symfony/process": "^2.5|^3.0"
+        "symfony/process": "^2.5|^3.0|^4.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^4.8.24",