https://techcrunch.com/2017/12/04/apple-pay-cash-starts-rolling-out-to-iphone-users-in-the-u-s/

Apple Pay Cash is finally starting to roll out to users in the States, bringing the ability to send other iOS users payments directly through iMessage. The update is arriving piece by piece to those who’ve downloaded iOS 11.2, which launched two days back with a not-yet-live version of the feature.

Apple Pay Cash was announced back in June at WWDC. However, the company added ahead of iOS 11’s September launch that the feature would be “coming this fall with an update to iOS 11 and watchOS 4,” and while it was intended to launch alongside 11.2, this weekend’s early arrival of operating system left it behind, as the company worked to push the software live, seemingly in order to address an issue that was causing some iPhones to randomly reboot.