Although the feature was showcased using 3D Touch on an iPhone 6S, the company writes in its release notes that rich notifications will support devices without the pressure-sensing technology:
"Support for rich notifications is optimized for 3D Touch, and in iOS 10 beta 1 the feature is available only on iPhone 6s and iPhone 6s Plus. Future betas will provide access to this functionality for users of iPhone models without support for 3D Touch."
Through rich notifications, users can easily type out a reply, or even show a live broadcast of an event. While it's unclear how rich notifications will work on older devices, some have speculated a long press.