Receipt Emails - Fixed Payment Amount
Our old default receipt email used to use the field {{product_price}} to tell a customer how much they just got charged. Trouble is, when you perform a one-time charge, its not necessarily in the amount of the price of their product!
So, we’ve introduced a new field: {{payment.amount}}
This field will return a currency-formatted representation of the amount the customer actually just paid.
To make use of this new field, you’ll need to change the occurrences of {{product_price}} to {{payment.amount}} in your receipt emails. If you’re using the default receipt email, we can almost do this for you - just click on the “Revert to default” link beneath the receipt email body on the Notifications tab.

Bonus: the object.method syntax used by this new variable is a harbinger of more replacement variables (and hence, better email customizations) to come!