When you update an WordPress theme your contents are totally safe, because the only thing that it’s affected are the theme files. The database isn’t touched. That also means that all changes you might have done to the theme files will be lost, you might need to reproduce them again in the new theme files.
Before updating the theme you should make a backup of your current theme folder, so you can recover some old file you might need later (or even the entire theme in the case something goes wrong during the upgrade). To backup your current theme folder just make a copy your current /wp-content/ themes/invicta/ folder.
Once you have the backup ready, you need to download the latest theme version. Login to ThemeForest, head over to your Downloads section and re-download the theme like you did when you bought it.
You can download the entire theme package or the installable WordPress file only. If you have downloaded the entire package, extract the zip content, locate the invicta.zip file and extract it too. If you have downloaded only the installable WordPress file, you only need to extract its zip content.
For both cases you should end up with the unzipped invicta theme folder.
Then upload that folder, using FTP, to the /wp-content/themes/ folder in your server, overwriting the
Once all the files are uploaded, you will need to restore your Theme Options settings, so the CSS rules can be rewritten to the theme’s CSS files. To do that, in your admin-area, navigate to Appearance > Theme Options and just click on the Save All Changes button. It’s done!
If you have ever changed the theme’s translation (.pot) files, you will need to restore them to, by recovering the languages folder from your backup. Just copy the languages folder form the old (and backed up theme’s folder) to the new theme’s folder.