Thank you sir. I know this. I have problems when I upgrate the website from joomla 3 to 4.
Before upgrating to joomla 4 I can see that "System - Helix Ultimate Framework" provided by an error as well. I went to components // joomla update // live update. There I can see in the list the "System - Helix Ultimate Framework" .
After the upgrating I had the error :
Cannot access protected property Joomla\CMS\Menu\MenuItem::$params
It gives the error: json_decode(): Argument #1 ($json) must be of type string, stdClass given
NOTE: I'm rebuilding the website from the beggining in joomla 4 (without upgrate). It will be VERY HELPFUL if in the future has an option to download all the conent (pages that I designed) into a file and be able to upload it in another website.