Hey Jdudeo,
first of all, thank you for the purchase!
Before speaking about theme updates, it is worth noting that the recommended way to customize WordPress themes (e.g. in case you’ve bought the theme and want to make certain changes in the template code or the insides of the css stylesheets) is by using child themes. Ikebana supports child themes, and the downloadable package contains a starter child theme in the “Ikebana-child” folder. You can find more information on using child themes on this official page by WordPress.
Regarding theme updates, I would recommend downloading the latest version of the theme from your ThemeForest account, extracting the theme folder, and simply uploading it into the /wp-content/themes/ directory via ftp, overwriting the existing theme folder. When posting new theme updates, I use the ThemeForest function which automatically notifies all buyers once a new version is available.
Should you have additional questions, do not hesitate to contact me!
Sincerely,
Andrew / Satori Studio