diff --git a/composer.json b/composer.json
index bd79b28..f97904e 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
         "validation"
     ],
     "require": {
-        "neos/flow": "^6.3",
+        "neos/flow": "^6.3.5",
         "php": "~7.4.0"
     },
     "autoload": {