http://wccftech.com/ios-11-1-beta-2-brings-back-3d-touch-app-switcher-gesture/

Other than introducing hundreds of new emoji characters, Apple brought back the 3D Touch app switcher gesture in iOS 11.1 Beta 2.

The release of iOS 11 sounded off a disappointed flavored cry in the iOS community as it marked the removal of the famous 3D Touch app switcher gesture. By simply hard pressing on the left edge of the display, you could simply switch between apps or enter the app switcher if you so wished. For reasons unknown Apple removed it while also promised that it would make a comeback in a future update to iOS 11. iOS 11.1 Beta 2 is that release, and if you have the latest update installed already, then you can try it out for yourself today.