Joomla 5 compatibility: Class "JToolBarHelper" not found

[Jefferson49]

Observed with Joomla 5.2.3, joomla-oauth2-server 1.0.0

Action: Backend, Component => Configure OAuth2

Stack Trace:
1 () JROOT/administrator/components/com_oauth2server/views/accountsetup/view.html.php:58
2 miniorangeoauthserverViewAccountSetup->addToolBar() JROOT/administrator/components/com_oauth2server/views/accountsetup/view.html.php:42
3 miniorangeoauthserverViewAccountSetup->display() JROOT/libraries/src/MVC/Controller/BaseController.php:697
4 Joomla\CMS\MVC\Controller\BaseController->display() JROOT/libraries/src/MVC/Controller/BaseController.php:730
5 Joomla\CMS\MVC\Controller\BaseController->execute() JROOT/administrator/components/com_oauth2server/oauth2server.php:40

[Jefferson49]

The error can be resolved by activating the backward compatibility plugin

System / Manage / Plugins / Behaviour - Backward Compatibility => Activate