diff --git a/src/OpenSearch/Client.php b/src/OpenSearch/Client.php
index 260bc6b1..5334b5fb 100644
--- a/src/OpenSearch/Client.php
+++ b/src/OpenSearch/Client.php
@@ -315,7 +315,7 @@ class Client
     public function __construct(
         TransportInterface|Transport $transport,
         callable|EndpointFactoryInterface $endpointFactory,
-        array $registeredNamespaces,
+        array $registeredNamespaces = [],
     ) {
         if (!$transport instanceof TransportInterface) {
             @trigger_error('Passing an instance of \OpenSearch\Transport to ' . __METHOD__ . '() is deprecated in 2.4.0 and will be removed in 3.0.0. Pass an instance of \OpenSearch\TransportInterface instead.', E_USER_DEPRECATED);
diff --git a/util/template/client-class b/util/template/client-class
index d674152c..eef11ad3 100644
--- a/util/template/client-class
+++ b/util/template/client-class
@@ -78,7 +78,7 @@ class Client
     public function __construct(
         TransportInterface|Transport $transport,
         callable|EndpointFactoryInterface $endpointFactory,
-        array $registeredNamespaces,
+        array $registeredNamespaces = [],
     ) {
         if (!$transport instanceof TransportInterface) {
             @trigger_error('Passing an instance of \OpenSearch\Transport to ' . __METHOD__ . '() is deprecated in 2.4.0 and will be removed in 3.0.0. Pass an instance of \OpenSearch\TransportInterface instead.', E_USER_DEPRECATED);