Joomla 4 and Maximenu Mobile system plugin ??

When the Maximenu Mobile System plugin is enabled in Joomla 4 I get this error:

Call to undefined method Joomla\CMS\Application\AdministratorApplication::isAdmin()

Call stack
# Function Location
1 () JROOT/plugins/system/maximenuckmobile/maximenuckmobile.php:67
2 plgSystemMaximenuckmobile->onAfterDispatch() JROOT/libraries/src/Plugin/CMSPlugin.php:285
3 Joomla\CMS\Plugin\CMSPlugin->Joomla\CMS\Plugin\{closure}() JROOT/libraries/vendor/joomla/event/src/Dispatcher.php:486
4 Joomla\Event\Dispatcher->dispatch() JROOT/libraries/src/Application/EventAware.php:111
5 Joomla\CMS\Application\WebApplication->triggerEvent() JROOT/libraries/src/Application/AdministratorApplication.php:148
6 Joomla\CMS\Application\AdministratorApplication->dispatch() JROOT/libraries/src/Application/AdministratorApplication.php:186
7 Joomla\CMS\Application\AdministratorApplication->doExecute() JROOT/libraries/src/Application/CMSApplication.php:278
8 Joomla\CMS\Application\CMSApplication->execute() JROOT/administrator/includes/app.php:63
9 require_once() JROOT/administrator/index.php:32

Hi
Maximenu Mobile System plugin is obsolete and has been replaced with Mobile Menu CK since long
www.joomlack.fr/en/joomla-extensions/mobile-menu-ck

this one is compatible with Joomla 4
CEd