diff --git a/Admin/Installer.php b/Admin/Installer.php
index 8941fef..1b24b7d 100755
--- a/Admin/Installer.php
+++ b/Admin/Installer.php
@@ -166,7 +166,7 @@ final class Installer extends InstallerAbstract
             : \Modules\SupplierManagement\Models\SupplierMapper::class;
 
         /** @var \Modules\ClientManagement\Models\Client|\Modules\SupplierManagement\Models\Supplier $person */
-        foreach ($mapper::yield()->execute() as $person) {
+        foreach ($mapper::yield()->executeYield() as $person) {
             $response = new HttpResponse();
             $request  = new HttpRequest();
 
diff --git a/Controller/ApiController.php b/Controller/ApiController.php
index b9860db..2b39d3c 100755
--- a/Controller/ApiController.php
+++ b/Controller/ApiController.php
@@ -447,7 +447,7 @@ final class ApiController extends Controller
                     // and then do normal algorithm like for a new element
                 }
                 */
-                if ($new->item->id !== $old->item->id) {
+                if ($new->item?->id !== $old->item?->id) {
                     // @todo: also undo stock amount in stock distribution
                     StockTransactionMapper::delete()->execute($transactions);