- 19 digit Visa and Discover cards

        - MasterCard 222100–272099 range
        - Canada does not process JCB 3529-3589 as Discover, but Puerto Rico,
          US Virgin Islans, Northern Mariana Islands, Palau and Guam do
        - China Union Pay only processed as Discover in the US, Mexico and
          the Caribbean, not elsewhere outside China
        - 14 digit Discover remain only in 36*
        - receipt_cardtype subroutine supporting Discover's new receipt
          requirements