Hello Joomshaper,
I finally installed the latest version of Educon and it works fine. I had always waited for a message for an update in the backend. Stupid of me. I'm afraid that my layout would be destroyed if I simply install the latest version of Educon.
But still, there are a few things that don't work like before. There is the extension SP LMS, which seems to cause problems in the database. Also, there are problems with the display of some icons, maybe it's fontawesome. The layout of the Joomla module "latest news" on the start page is ruined. The search has also lost its layout. In the backend, under the vertical menu on the left, an entry "SP Page Builder" appears, which has no function at all. Many thanks for your efforts. Jens