Please create a back up of your site and database and update all plugins to the latest versions as well as WordPress.
We don’t update plugins as we aren’t their developers. The plugins are always updated by their authors.
Please take our apologies.
We have updated Visual Composer on our test sites and haven’t seen any issues. All sites are working fine without any errors.
You can enable debug mode in wp-config.php file http://codex.wordpress.org/Debugging_in_WordPress and check your site for any errors or warnings that may cause issues.
Could you please specify or show screenshot what error messages you were getting?