Hi Richard,
Update Download and Instructions
Please note: make a backup of the Theme inside your WordPress installation folder/wp-content/themes/interface pro
To update the Theme, login to your account, head over to your downloads section and re-download the theme like you did when you bought it.
Extract the zip’s contents, look for the extracted theme folder, and after you have all the new files upload them using FTP to the /wp-content/themes/interface pro folder overwriting the old ones (this is why it’s important to backup any changes you’ve made to the theme files ).
If you didn’t make any changes to the theme files, you are free to overwrite them with the new ones without the risk of losing theme settings, pages, posts, etc, and backwards compatibility is guaranteed.
Thank you!