diff --git a/src/Client/RedmineClient.php b/src/Client/RedmineClient.php
index 251d0e8..72f075f 100644
--- a/src/Client/RedmineClient.php
+++ b/src/Client/RedmineClient.php
@@ -29,7 +29,7 @@ final class RedmineClient
     }
 
 
-    public function __call($name, $arguments)
+    public function __call(mixed $name, mixed $arguments): mixed
     {
         if (!method_exists($this->client, $name)) {
             throw new \BadMethodCallException(sprintf(