diff --git a/composer.json b/composer.json
index 7ba9aeaa1d3b2c1f0802f6220af12758ba4336cf..e84dd955efd66a322b1b7edb103972c587de9679 100644
--- a/composer.json
+++ b/composer.json
@@ -22,6 +22,9 @@
         "sort-packages": true,
         "platform": {
             "php": "7.3"
+        },
+        "allow-plugins": {
+            "symfony/flex": true
         }
     },
     "autoload": {