diff --git a/src/Socialbox/Classes/StandardMethods/Settings/SettingsInformationFieldExists.php b/src/Socialbox/Classes/StandardMethods/Settings/SettingsInformationFieldExists.php
index 3823e81..21eb9e7 100644
--- a/src/Socialbox/Classes/StandardMethods/Settings/SettingsInformationFieldExists.php
+++ b/src/Socialbox/Classes/StandardMethods/Settings/SettingsInformationFieldExists.php
@@ -27,7 +27,8 @@
             {
                 throw new MissingRpcArgumentException('field');
             }
-            $fieldName = InformationFieldName::tryFrom(strtoupper($rpcRequest->getParameter('field')));
+
+            $fieldName = InformationFieldName::tryFrom(strtoupper((string)$rpcRequest->getParameter('field')));
             if($fieldName === null)
             {
                 throw new InvalidRpcArgumentException('field');