Yes! All your recent order history and account details (addresses, payment options, credit, etc) have been brought across to the new website so you can view and manage everything from your dashboard with great ease.
Any existing credit amount that you have against your account will be automatically applied in the checkout when you complete your next order, or when your next subscription order is processed. In the checkout, there will also be fields where you can add promo codes and gift cards you received before the website update.