Why can't Apple 7 send invisible messages?

Press the send button with 3D TOUCH for 6S and above models, and press the send button with long press for 6 and below models and iPad.

Apple's 6S and mobile phones upgraded to iOS 10 have the function of invisible ink. First, select "Settings-Accessibility-Turn on 3DTouch" in turn, then enter text in the information input interface, and then press and hold the blue arrow on the right to select special effects.

It is only possible to turn off the weakening dynamic effect in the auxiliary function and 3D Touch at the same time, and if the iMessage function is turned on, the other party is also an Apple user, and it is only possible for systems with IOS 10 and above. I often send invisible ink messages.

Turn off the weakened dynamic effect and 3D Touch in the auxiliary function, and send it in the case of iMessage. And it can only be sent between Apple users.