diff --git a/composer.json b/composer.json
index 545ce81..c6ebe58 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,7 @@
         "php": ">=5.5",
         "doctrine/collections": "~1.0",
         "symfony/filesystem": "^2.0.5 || ^3.0 || ^4.0",
-        "symfony/process": "^3.0 || ^4.0",
+        "symfony/process": "^3.4 || ^4.0",
         "symfony/polyfill-mbstring": "^1.3"
     },
     "require-dev": {