It’s very important to keep your theme up to date for bug and security fixes and to receive new features. You can always visit the changelog to see the latest version of the theme available for purchase/download. But you can also just setup automatic updates so you can be notified about new versions of the theme.
To find out what your current version is you have to options:
Option 1: Check the Theme Panel
You can easily view your theme version in the main theme panel.
Option 2: Check Under Appearance > Themes
Go to Appearance > Themes locate the total theme and then click on it to view the version number.