diff --git a/composer.json b/composer.json
index 937dd74..6bf981d 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
     "php": "^7.0",
     "pimple/pimple": "^3.0",
     "monolog/monolog": "^1.17",
-    "symfony/validator": "^3.0",
+    "symfony/validator": "^3.0 || ^4.0",
     "symfony/yaml": "^2.8 | ^3.0",
     "ext-json": "*"
   },