date after which merchants are supposed to be liable for fraudulent purchases made with old-style cards, and are supposed to have point of sale terminals that accept "chip and PIN" cards.
It's the date after which merchants are supposed to be liable for fraudulent purchase made with New-style chip and Signature cards which are made as swipe transactions (e.g. with an old terminal).
TFIFY. The new US cards are chip and signature, not chip and PIN. At least, they are not required to be chip and PIN. Which is very unfortunate.