diff --git a/CHANGELOG.md b/CHANGELOG.md
index fb86d54..623d31d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,11 +7,19 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 
 ## Unreleased
 
+
+## 2.5.7 - 2021-04-09
+
+### Fixed
+- Fixed an issue where order dates weren’t being sent to Vend with time zones. The format now conforms to RFC3339.
+
+
 ## 2.5.6 - 2021-03-11
 
 ### Fixed
 - Fixed an issue where order level discounts weren’t showing the tax inside them
 
+
 ## 2.5.5 - 2021-01-05
 
 ### Fixed
diff --git a/src/services/Orders.php b/src/services/Orders.php
index cecd17a..1e8a19f 100644
--- a/src/services/Orders.php
+++ b/src/services/Orders.php
@@ -19,6 +19,7 @@
 use craft\commerce\models\LineItem;
 use craft\commerce\Plugin as CommercePlugin;
 use craft\helpers\Json;
+use DateTimeInterface;
 use Exception;
 use Throwable;
 use yii\base\InvalidConfigException;
@@ -203,12 +204,12 @@ public function registerSale(int $orderId) {
             'customer_id' => $vendCustomerId,
             'user_id' => $settings->vend_userId,
             'status' => 'CLOSED',
-            'sale_date' => $order->dateOrdered->format('Y-m-d H:i:s'),
+            'sale_date' => $order->dateOrdered->format(DateTimeInterface::RFC3339),
             'register_sale_products' => [],
             'register_sale_payments' => [
                 [
                     'retailer_payment_type_id' => $settings->vend_retailerPaymentTypeId,
-                    'payment_date' => $order->dateOrdered->format('Y-m-d H:i:s'),
+                    'payment_date' => $order->dateOrdered->format(DateTimeInterface::RFC3339),
                     'amount' => $order->getTotalPaid()
                 ]
             ]