How to update a product as sold?

I saw on few websites products marked as sold (which is also a good way to promote the sales).
How we can do that?
Thank you!

Hi,
You'll be able to do that by :
- Creating a category where you'll add all your "sold" products
- Create a badge through "Hikashop->Products->Badges" and don't forget to add your category through the "Category" restriction.