Flat Responsive was updated to version 1.0.6 with a few bug fixes. You can check the changes here.
WordPress 4.3 Compatibilty bug fixed
Testimonial bug fixed [undefined error]
Portfolio bug fixed [undefined error]
Language translation ready file change according to text-domain
Font awesome icons update
Hide title issue bug fixed
NOTE: A reminder that if you made any changes to the theme’s files, including the style.css file, these will be overwritten. It’s also recommended you make a copy of your theme and save it somewhere as a backup.