Hey you should re purchase theme's license to get the updated version also there are so many changes in new version so the upgrade can only be done by us cause we know everything and we can do it quickly.
About WooCommerce Checkout and cart pages please check in wp-admin >> pages if those pages exists there. If yes open them and see if they have WooCommerce proper shortcodes.
For more support please re purchase theme so we can help you more , there should be no prolem to run WooCommerce on the version of theme you are using. So check Woo settings and its pages