[Theme Horse Support Team]

Hi Thomas,

You can easily directly update the free WordPress directory themes but for the premium themes which are not listed on WordPress directory you need to update it manually.
To update the theme to the latest version first activate any other themes than delete the previous version of Interface Pro theme and then upload the new version of Interface Pro (.zip) file that you have downloaded on your computer and activate it.

Note: If you have customize the theme main code then make sure first you backup it before deleting the previous version from your site.

Thank you!