If you want to update Visual Composer or any other premium plugin included in our theme do this manually http://xstore.helpscoutdocs.com/article/37-plugins-update using the latest archives that you can find here https://www.8theme.com/download-plugins/
All the premium plugins included in our theme are external and we have the right to build them into our theme as we purchase the Extended License for each of these plugins. The plugins run perfectly and are fully functional. There is no doubt that you can get the current plugin version directly from us.
These plugins registration is not obligatory! The plugins are functioning perfect without any activation.
The plugin activation option was added in the plugin for the customers to get automatic updates and support directly from plugin developers. Only in case you need this features you will need to purchase and register the plugin. This is not only our practice but all the theme authors from ThemeForest.