diff --git a/src/GW2Api.php b/src/GW2Api.php
index <HASH>..<HASH> 100644
--- a/src/GW2Api.php
+++ b/src/GW2Api.php
@@ -60,7 +60,7 @@ class GW2Api {
         $handler->push(EffectiveUrlMiddleware::middleware());
 
         return [
-           'base_url' => $this->apiUrl,
+           'base_uri' => $this->apiUrl,
            'defaults' => [
                'verify' => $this->getCacertFilePath()
            ],
fix base_uri
guzzle 6 changed the name of this option