diff --git a/appstore/notification.go b/appstore/notification.go
index c2c2abd..9637a5d 100644
--- a/appstore/notification.go
+++ b/appstore/notification.go
@@ -43,6 +43,7 @@ type NotificationReceipt struct {
 	TransactionID             string `json:"transaction_id"`
 	OriginalTransactionID     string `json:"original_transaction_id"`
 	IsTrialPeriod             string `json:"is_trial_period"`
+	IsInIntroOfferPeriod      string `json:"is_in_intro_offer_period"`
 
 	PurchaseDate
 	OriginalPurchaseDate