It isn’t clear when the new card readers will be purchased, officials said, but they are needed to fulfill one of the early promises of the Key system — that it would be possible to pay for a ride without SEPTA’s proprietary cards. The system was designed to allow riders to pay with a credit card, an app, or a digital wallet, but in recent weeks, SEPTA learned the current machines can’t be upgraded to comply with banks’ standards. New hardware was needed.