Finally, after several tests with jquery versions I found that the correct one was the jquery-1.8.0.min.js. Is the only one latest jquery version which is working with superfish.js. The jQuery versions after 1.8.0 seem to have problems working in combination with superfish.js (also tested the latest jQuery 3.1.1 with no result). So eventually I had to upload the jquery-1.8.0.min.js in the js directory and modify the theme-scripts.php for the file and version of jQuery.
