This page normally provides links for minor version updates to the latest version. For example, if the latest version were 6.2.7, and your version was 6.1.3, you could download a free upgrade to 6.2.7 on this page. If the first digit of your version number were earlier than the first digit of the current version, however, this would be a major version upgrade, and the upgrade would not be free.
No minor version updates are available as yet, because the current version is 7.0.0. Family Historian will automatically check for updates for you, and alert you when one becomes available.