Oneplus2, screen capture option disappeared after OS upgrade I have a Oneplus2 device, recently (last week) I have upgrades the OS to OxygenOS 3.5.6. Among a lot of UI changes I have noticed that when I long press the power button I only get the "Power off" and "Reboot" options. 

Before the OS upgrade It also contained a capture screen (for screenshots) button. Is there a way to bring it back ?
This feature is dropped from the OS update and you would need root pets to attempt restore or apply a hack. Since your device is not rooted, you can use Three Finger Swipe . Steps below :

Settings &rarr; Gestures &rarr; Enable Three Finger screenshot

By swiping the fingers from top down, you can take a screenshot. There's also an option of taking  a long screenshot by pressing the icon which looks like portrait device icon

I neither have the device nor OS, but saw it on a friend's device. Please feel free to add or edit