If you see this message while for example uploading images to DJ-Catalog component follow this short guide.

Your browser doesn't support HTML5, Flash, Silverlight and even HTML4! Please upgrade your browser!

This problem is related to file upload area in DJ-Catalog2 and other extensions that using plmultiupload script like DJ-Mediatools or DJ-Classifieds.

Why the problem appears?

In most cases, the problem is related to JavaScript. The error may occur after Joomla 3.7 update or if there is a script conflict between extensions.

How to fix the problem?

Simply update extensions (eg. DJ-Catalog2) to newest versions and clear browser cache (CTRL + F5).

Install and enable DJ-jQuery-Monster plugin in order to get rid of jQuery conflicts.