Joomla 4 incompatibilit error when updating Order Status from dropdown selection

-- HikaShop version -- : HikaShop Business: 5.0.3
-- Joomla version -- : 4.4.3
-- PHP version -- : 8.2
-- Error-message(debug-mod must be tuned on) -- : An error has occurred.
0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()
Call stack
# Function Location
1 () JROOT/media/com_hikashop/mail/order_status_notification.preload.modified.php:62
2 include() JROOT/administrator/components/com_hikashop/classes/mail.php:362
3 hikashopMailClass->loadEmail() JROOT/administrator/components/com_hikashop/classes/mail.php:31
4 hikashopMailClass->get() JROOT/administrator/components/com_hikashop/classes/order.php:2087
5 hikashopOrderClass->loadOrderNotification() JROOT/administrator/components/com_hikashop/views/order/view.html.php:491
6 OrderViewOrder->changestatus() JROOT/administrator/components/com_hikashop/views/order/view.html.php:28
7 OrderViewOrder->display() JROOT/libraries/src/MVC/Controller/BaseController.php:660
8 Joomla\CMS\MVC\Controller\BaseController->display() JROOT/administrator/components/com_hikashop/helpers/helper.php:2577
9 hikashopController->display() JROOT/administrator/components/com_hikashop/controllers/order.php:179
10 OrderController->changestatus() JROOT/libraries/src/MVC/Controller/BaseController.php:693
11 Joomla\CMS\MVC\Controller\BaseController->execute() JROOT/administrator/components/com_hikashop/helpers/helper.php:2555
12 hikashopController->execute() JROOT/administrator/components/com_hikashop/hikashop.php:73
13 require_once() JROOT/libraries/src/Dispatcher/LegacyComponentDispatcher.php:71
14 Joomla\CMS\Dispatcher\LegacyComponentDispatcher::Joomla\CMS\Dispatcher\{closure}() JROOT/libraries/src/Dispatcher/LegacyComponentDispatcher.php:73
15 Joomla\CMS\Dispatcher\LegacyComponentDispatcher->dispatch() JROOT/libraries/src/Component/ComponentHelper.php:361
16 Joomla\CMS\Component\ComponentHelper::renderComponent() JROOT/libraries/src/Application/AdministratorApplication.php:143
17 Joomla\CMS\Application\AdministratorApplication->dispatch() JROOT/libraries/src/Application/AdministratorApplication.php:186
18 Joomla\CMS\Application\AdministratorApplication->doExecute() JROOT/libraries/src/Application/CMSApplication.php:293
19 Joomla\CMS\Application\CMSApplication->execute() JROOT/administrator/includes/app.php:61
20 require_once() JROOT/administrator/index.php:32

Changing order status works fine when doing it from within the order page, but this error is thrown when using the dropdown on the Orders page in administrator. Tried disabling all Hikashop plugins, disabling all Emails, no change.

You are correct. Changing the file name fixed things. However, I should say that I unpublished this file in the backend System -> Emails and nothing changed with the error. That's why I thought it wasn't this file.