Visual composer not working

I’m not able to get Visual Composer to work on my site. I’m running version 2.4.2 of HighEnd (WP version 4.7.2). And WPBakery Visual Composer version 4.5.2.

I’m reluctant to update HighEnd because I don’t to have any problems with our current site. I’m happy with the current functionality and don’t want anything to break.

Is there any way to fix Visual Composer so we can update the content on our site without having to update the theme? If not, is there a risk in losing functionality or date by updating the theme?

Thanks.