- Set up a plan family with a migration path. Make sure that the products in the migration path are mapped and that discounts are set to be passed over.
- Set up a customer with the source plan. Activate the source subscription before applying any coupons or discounts.
- Add discount(s) to the source subscription's products either manually or through a coupon.
- Migrate the source subscription to the destination subscription before the source subscription goes through a renewal.
There is no known workaround at this time. However, when migrating a subscription after the discount has already been applied to a posted invoice (such as by applying a coupon before activating the subscription) the discount is correctly applied to the first invoice of the destination subscription.