diff --git a/src/Enum/Fields/MetafieldFields.php b/src/Enum/Fields/MetafieldFields.php
index 6227dc5..b517a54 100644
--- a/src/Enum/Fields/MetafieldFields.php
+++ b/src/Enum/Fields/MetafieldFields.php
@@ -8,7 +8,7 @@ class MetafieldFields extends AbstractObjectEnum
     const DESCIRPTION = 'description';
     const ID = 'id';
     const KEY = 'key';
-    const NAMESPACE = 'namespace';
+    const METAFIELD_NAMESPACE = 'namespace';
     const OWNER_ID = 'owner_id';
     const OWNER_RESOURCE = 'owner_resource';
     const VALUE = 'value';
diff --git a/src/Enum/Fields/OrderFields.php b/src/Enum/Fields/OrderFields.php
index 95a1cd0..19475b5 100644
--- a/src/Enum/Fields/OrderFields.php
+++ b/src/Enum/Fields/OrderFields.php
@@ -19,6 +19,7 @@ class OrderFields extends AbstractObjectEnum
     const CUSTOMER_LOCALE = 'customer_locale';
     const DISCOUNT_CODES = 'discount_codes';
     const EMAIL = 'email';
+    const CONTACT_EMAIL = 'contact_email';
     const FINANCIAL_STATUS = 'financial_status';
     const FULFILLMENTS = 'fulfillments';
     const FULFILLMENT_STATUS = 'fulfillment_status';
@@ -50,6 +51,7 @@ class OrderFields extends AbstractObjectEnum
     const TOTAL_DISCOUNTS = 'total_discounts';
     const TOTAL_LINE_ITEMS_PRICE = 'total_line_items_price';
     const TOTAL_PRICE = 'total_price';
+    const TOTAL_PRICE_USD = 'total_price_usd';
     const TOTAL_TAX = 'total_tax';
     const TOTAL_WEIGHT = 'total_weight';
     const UPDATED_AT = 'updated_at';
@@ -64,10 +66,11 @@ public function getFieldTypes()
             'browser_ip' => 'string',
             'buyer_accepts_marketing' => 'boolean',
             'cancel_reason' => 'string',
-            'cancelled_at' => 'boolean',
+            'cancelled_at' => 'DateTime',
             'cart_token' => 'string',
             'client_details' => 'object',
             'closed_at' => 'DateTime',
+            'contact_email' => 'string',
             'created_at' => 'DateTime',
             'currency' => 'string',
             'customer' => 'Customer',
@@ -105,6 +108,7 @@ public function getFieldTypes()
             'total_discounts' => 'string',
             'total_line_items_price' => 'string',
             'total_price' => 'string',
+            'total_price_usd' => 'string',
             'total_tax' => 'string',
             'total_weight' => 'string',
             'updated_at' => 'DateTime',
diff --git a/src/Service/MetafieldService.php b/src/Service/MetafieldService.php
new file mode 100644
index 0000000..26bf8d5
--- /dev/null
+++ b/src/Service/MetafieldService.php
@@ -0,0 +1,113 @@
+<?php
+
+namespace Shopify\Service;
+
+use Shopify\Object\Metafield;
+
+class MetafieldService extends AbstractService
+{
+    /**
+     * Retrieve a list of metafields that belong to a resource
+     *
+     * @link   https://help.shopify.com/api/reference/metafield#index
+     * @param array $params
+     * @param string $ownerResource
+     * @param string $ownerId
+     * @return Metafield[]
+     */
+    public function all(array $params = array(), $ownerResource = '', $ownerId = '')
+    {
+        if ($ownerResource && $ownerId) {
+            $endpoint = '/admin/' . $ownerResource . '/' . $ownerId . '/metafields.json';
+        } else {
+            $endpoint = '/admin/metafields.json';
+        }
+        $response = $this->request($endpoint, 'GET', $params);
+        return $this->createCollection(Metafield::class, $response['metafields']);
+    }
+    /**
+     * Receive a count of all metafields
+     *
+     * @link   https://help.shopify.com/api/reference/metafield#count
+     * @param  array $params
+     * @return integer
+     */
+    public function count(array $params = array())
+    {
+        $endpoint = '/admin/metafields/count.json';
+        $response = $this->request($endpoint, 'GET', $params);
+        return $response['count'];
+    }
+    /**
+     * Receive a single metafield
+     *
+     * @link   https://help.shopify.com/api/reference/metafield#show
+     * @param  integer $metafieldId
+     * @param  array   $fields
+     * @return Metafield
+     */
+    public function get($metafieldId, array $fields = array())
+    {
+        $params = array();
+        if (!empty($fields)) {
+            $params['fields'] = $fields;
+        }
+        $endpoint = '/admin/metafields/'.$metafieldId.'.json';
+        $response = $this->request($endpoint, 'GET', $params);
+        return $this->createObject(Metafield::class, $response['metafield']);
+    }
+    /**
+     * Create a new metafield for a resource
+     *
+     * @link   https://help.shopify.com/api/reference/metafield#create
+     * @param  Metafield $metafield
+     * @param string $ownerResource
+     * @param string $ownerId
+     * @return void
+     */
+    public function create(Metafield &$metafield, $ownerResource = '', $ownerId = '')
+    {
+        $data = $metafield->exportData();
+        if ($ownerResource && $ownerId) {
+            $endpoint = '/admin/' . $ownerResource . '/' . $ownerId . '/metafields.json';
+        } else {
+            $endpoint = '/admin/metafields.json';
+        }
+        $response = $this->request(
+            $endpoint, 'POST', array(
+                'metafield' => $data
+            )
+        );
+        $metafield->setData($response['metafield']);
+    }
+    /**
+     * Modify an existing metafield
+     *
+     * @link   https://help.shopify.com/api/reference/metafield#update
+     * @param  Metafield $metafield
+     * @return void
+     */
+    public function update(Metafield &$metafield)
+    {
+        $data = $metafield->exportData();
+        $endpoint = '/admin/metafields/'.$metafield->id.'.json';
+        $response = $this->request(
+            $endpoint, 'PUT', array(
+                'metafield' => $data
+            )
+        );
+        $metafield->setData($response['metafield']);
+    }
+    /**
+     * Remove a metafield
+     *
+     * @link   https://help.shopify.com/api/reference/metafield#destroy
+     * @param  Metafield $metafield
+     * @return void
+     */
+    public function delete(Metafield &$metafield)
+    {
+        $endpoint = '/admin/metafields/'.$metafield->id.'.json';
+        $this->request($endpoint, 'DELETE');
+    }
+}