Apple has quietly discontinued its iOS Cards app that allowed users to customize, order, and automatically mail out letters. The app was introduced nearly two years ago alongside the iPhone 4S, but it was never included on a device by default. Though the app wasn't Apple's first foray into printing — it had done that for years in iPhoto — it was billed as a fun and simple way to get just a little more tactile at a time when most cards are going digital. Apple says that all cards ordered before 4PM ET yesterday, shortly after its press conference, will be delivered, but suggests that interested parties should head back over to iPhoto for future letter customizations, where a similar tool continues to function.