I like this theme and I updated to this version because I used other previous version named Bootstrap eCommerce...the theme works fine soon.
You only have to make some little readjustments if you were using the previous theme just because it had a different name.
My suggestion is create a new child theme and copy in it the previous custom style.css. Then open this file in a notepad and change only the child theme name, parent theme name and parent style.css reference. Save and upload to your site or copy and paste it in the WP editor.
Great Work boys!