Apple's 'iPhone 8' may allow triggering Siri by holding sleep/wake button
To get around the absence of a physical home button, the "iPhone 8" may let people trigger Siri by holding down the sleep/wake button when they're not using "Hey Siri."

The option was allegedly uncovered in source code by Brazilian iOS developer Guilherme Rambo. He didn't say immediately identify which code, but Rambo was previously responsible for uncovering secrets from leaked Apple HomePod firmware, including the "iPhone 8's" apparent "SmartCam" feature.
Without a home button, Apple is reportedly having to make major interface adjustments for the "iPhone 8," implementing new gestures and a "software bar," as well as replacing Touch ID with 3D facial recognition. The company could conceivably put Siri in the software bar, but there have been no rumors to that effect yet.
Apple will finally reveal the phone at a Sept. 12 press event. The company is also expected to show off the "iPhone 7s" and "7s Plus,", an LTE-equipped Apple Watch, and a new Apple TV with 4K and HDR support.
Rambo recently claimed that the FCC identifier for the Apple TV is "BCGA1842," while a Canadian equivalent is "579C-A1842." The FCC number didn't show up in an AppleInsider database search.

The option was allegedly uncovered in source code by Brazilian iOS developer Guilherme Rambo. He didn't say immediately identify which code, but Rambo was previously responsible for uncovering secrets from leaked Apple HomePod firmware, including the "iPhone 8's" apparent "SmartCam" feature.
Without a home button, Apple is reportedly having to make major interface adjustments for the "iPhone 8," implementing new gestures and a "software bar," as well as replacing Touch ID with 3D facial recognition. The company could conceivably put Siri in the software bar, but there have been no rumors to that effect yet.
Apple will finally reveal the phone at a Sept. 12 press event. The company is also expected to show off the "iPhone 7s" and "7s Plus,", an LTE-equipped Apple Watch, and a new Apple TV with 4K and HDR support.
Rambo recently claimed that the FCC identifier for the Apple TV is "BCGA1842," while a Canadian equivalent is "579C-A1842." The FCC number didn't show up in an AppleInsider database search.
Comments
Removing the home button causes more problems than it resolves.
But seriously—double click can bring up other UI.
That does seem sloppy and cumbersome, but unless there's a touch-sensitive area on the sides of the device, like with whichever Android-based device that can be squeezed, I don't have a better solution.
I will note that in iOS 11 they've already added a multifaceted feature when you press the Sleep/Wake button 5 times. Not only will it allow an emergency number to be called and disable Touch ID (and I guess Face ID if the rumours are true), but also provides the standard slider to turn off the device.
But what if you need a hard power cycle? Will holding it down do the trick? Could this be a logistics issue if it's pressed against something in your pocket or bag, which one could argue is why Macs have a single button for a hard power cycle and iPhones have required you hold down two buttons (first the Home and Sleep/Wake, and then the Volume Up and Sleep/Wake once the Home button became a static button).
Maybe you press the Volume Up and Sleep/Wake button together to get the power off slider, but if that's the case my picture taking is going to be awkward as I can't seem to not press those two buttons at the same time.
The solution is simple: double-click to bring up power-down UI or move it to a software-only area (like rotation on iPad).
Note that holding down the power button indefinitely would still force the phone to power down. Given this they could bring up the power down UI here also, should they wish to. So a double-click or a semi-indefinite hold (beyond Siri) could reveal the power down UI.
Plenty of options. And they've had a while to think about this, so there's no reason the solution can't be sensible. A double-click is sensible.
🙄
Why not hold down both volume buttons at the same time