Hello,
Thank you for reaching out to us.
Please download XStore – Installable Archive from this page https://www.8theme.com/downloads , go to Appearance > Themes > Add New > Upload archive > Install > Replace with uploaded.
Then, download the Core plugin archive from this page – https://www.8theme.com/downloads/
Go to Dashboard > Plugins > Add new > Upload plugin > Choose plugin (downloaded from https://www.8theme.com/downloads) > Install now > click on “Replace current with uploaded”.
Then, clear all caches and check how Theme Options work.
Best Regards,
8Theme’s Team