diff --git a/composer.json b/composer.json
index f5b7c4f..dcb55aa 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
     ],
     "require": {
         "php": ">=8.1",
-        "fp4php/functional": "^4.20",
+        "fp4php/functional": "^4.20|^6",
         "symfony/dependency-injection": "^5.4|^6|^7",
         "symfony/http-kernel": "^5.4|^6|^7"
     },