The Product Key validates your purchase and enables updates for both the theme and the plugins coming with it (i.e. Visual Composer).
How to generate a Product Key?
Navigate to The Shopkeeper > Product Key and click the “Generate a product key” button. The page opening in a new tab will ask you sign-in using your Envato account. That’s just like logging in with Facebook, but it’s your Envato account instead. By doing so, we won’t have to ask you to register for a new account or provide purchase codes when you update the theme or if you reach out for support.
Yes, sure, you can always go back to my.getbowtied.com to change the domain name and generate a new Product Key for it.
There's clearly a need for having a secondary site (local, dev or staging environment) where you safely perform tests such as development, theme or plugins updates, etc before doing it on a live site so we kept that in mind for the product key validation. To activate your staging environment, when generating a product key, instead or typing in the main domain only, add your local/staging environment url as well, comma separated. Example:
This will allow you to use the same product key and validate both instances.