We always try to make Jkreativ more user friendly when our customer work with it, even on updating themes and required plugins. But in this case especially for Visual Composer and on another required plugins as well, we have been make several change on those plugin to fit with Jkreativ.
So please only use visual composer version that come with the themes. Update the visual composer outside of the themes (automatic update) version may cause your website break.
Let me know if you have further question or something problem in there.