https://www.theverge.com/circuitbreaker/2017/9/21/16346958/iphone-3d-touch-multitasking-coming-back-ios-11

Apple executive Craig Federighi has apparently confirmed that a popular 3D Touch gesture for the iPhone that was removed in iOS 11.0 will be returning in an upcoming software update. The gesture was a quick way of getting to the multitasking screen, and required just a firm press on the left edge of the screen and a flick right to bring up the app switcher.

According to an email published by MacRumors, Federighi said that Apple had to temporarily pull the useful shortcut “due to a technical constraint.” Apparently the company has now managed to overcome that issue and restore it, with Federighi promising “we will be bringing it back in an upcoming iOS 11.x update.”