GravityStripe Upgrade/Downgrade Demo GravityStripe Upgrade/Downgrade Demo Set a page with your upgrade/downgrade form. This page will be linked from your subscribers' area. Your Name* Your Email* Demo Subscription Price: Demo Total $0.00 Demo Credit CardUse "4242 4242 4242 4242" for the test card number, a valid expiration date in the future, and any random CVC number, to create a successful demo payment.Card Details Cardholder Name Return to the Demo