1. Log in to the admin section of your blog. (yourblog.com/ghost)
  2. At the bottom left, click on the dropdown arrow, and click on About Ghost
    Dropdown menu
  3. On this page, you will see the current version of your Ghost blog.
    Ghost Version

Direct URL: yourblog.com/ghost/#/about
To find the latest release of Ghost: https://github.com/TryGhost/Ghost/releases