How to update the theme & plugins:
The easiest way to update the theme is to rename the old theme as theme-name-old in your wp-content/themes folder. Then you will be able to upload the new theme theme-name.zip via the WordPress admin panel and activate it.
After the theme update, please proceed to Appearance > Theme Plugins, and update all the suggested plugins.
Note: Please deactivate the Layer slider plugin before update.