Hello,

In Joomla 3 I am using a plugin that changes my custom.less file to tot custum.css. But when I install this less plugin to a Joomla 4 website, the whole website shuts down and I get this message: "An error has occurred. 0 Call to undefined method Joomla\CMS\Application\AdministratorApplication::isSite()"

Can you inform me what this message means and if it is possible to use a plugin in Joomla 4 to chance a custom.less file in custom.css in Joomla 4?

With kind regeards,