Can I still redeem my Humble Game Making PlayCanvas Key?

I only just realized I had a key for this site, and I would like to redeem it. However, I can’t see the “promotional code” section on the account section? Can I still redeem the key?

Our website has changed slightly. Go to your account page and find the button which says UPGRADE. Click this and you will see a list of the available plans. At the bottom of this list is a field to enter your promo code. Enter your code and click Submit. This will redeem your code.