diff --git a/controllers/front/notify.php b/controllers/front/notify.php
index 0c6def53..2e6b2d43 100755
--- a/controllers/front/notify.php
+++ b/controllers/front/notify.php
@@ -66,8 +66,14 @@ public function postProcess()
             $secureKey
         ));
 
-        if (!$lockResult->isSuccessful()) {
-            die($this->module->l('Lock already exist', self::FILENAME));
+        if (!SaferPayConfig::isVersion17()) {
+            if ($lockResult > 200) {
+                die($this->module->l('Lock already exists', self::FILENAME));
+            }
+        } else {
+            if (!$lockResult->isSuccessful()) {
+                die($this->module->l('Lock already exists', self::FILENAME));
+            }
         }
 
         if ($cart->orderExists()) {
@@ -96,7 +102,6 @@ public function postProcess()
 
             $checkoutData->setOrderStatus($transactionStatus);
 
-            $checkoutProcessor->run($checkoutData);
             $orderId = $this->getOrderId($cartId);
 
             //TODO look into pipeline design pattern to use when object is modified in multiple places to avoid this issue.
diff --git a/controllers/front/return.php b/controllers/front/return.php
index 473997c4..1ce79fd0 100755
--- a/controllers/front/return.php
+++ b/controllers/front/return.php
@@ -175,10 +175,6 @@ private function executeTransaction($orderId, $selectedCard)
         );
     }
 
-    private function assertTransaction($cartId) {
-
-    }
-
     /**
      * @param int $cartId
      *
diff --git a/src/Controller/AbstractSaferPayController.php b/src/Controller/AbstractSaferPayController.php
index d62b5e46..cac8b4a2 100755
--- a/src/Controller/AbstractSaferPayController.php
+++ b/src/Controller/AbstractSaferPayController.php
@@ -82,6 +82,10 @@ protected function applyLock($resource)
             $this->lock->create($resource);
 
             if (!$this->lock->acquire()) {
+
+                if (!SaferPayConfig::isVersion17()) {
+                    return  http_response_code(409);
+                }
                 return Response::respond(
                     $this->module->l('Resource conflict', self::FILE_NAME),
                     Response::HTTP_CONFLICT
@@ -93,12 +97,20 @@ protected function applyLock($resource)
             $logger->payload = $resource;
             $logger->save();
 
+            if (!SaferPayConfig::isVersion17()) {
+                return  http_response_code(500);
+            }
+
             return Response::respond(
                 $this->module->l('Internal error', self::FILE_NAME),
                 Response::HTTP_INTERNAL_SERVER_ERROR
             );
         }
 
+        if (!SaferPayConfig::isVersion17()) {
+            return  http_response_code(200);
+        }
+
         return Response::respond(
             '',
             Response::HTTP_OK