Hello,
The thing is that the coupon generator store the coupon end date into the serial extra data ( discount_end ).
So if you want to display the date, you just need to display that " serial.extradata.discount_end " information and use the "date" format to transform the timestamp into a formatted date.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.