You can check your theme version by going to the Appearance > Themes section of your dashboard. Click on the theme in this page and it will display the version number, and also say if there is an update available.
It is important to keep your theme and plugins updated to the latest version. This will mean that any new features and bugfixes are applied to your site.
To check for a theme update, you should go to Appearance > Themes in your dashboard. If a theme update us available, it will look like the below example:
To complete the update, simply click “Update now”.