iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
'Quick Snap' Maps iPhone Volume Buttons to Camera Shutter (For Now)
But just as Apple appears to have let Camera+ out of the penalty box and back into the store (without the volume button feature present), another new app has been approved that not only offers this same functionality, but features it prominently in the app's description and screenshots. Quick Snap - Camera Plus ($1.99), released on December 15th, was noted by Wired for its curious offering of the banned feature.
Turn iPhone Volume Button into a Shutter Button? "Quick Snap" is the app for THAT!
Why choose the soft or full screen shutter when you can use VOLUME BUTTON as the hard shutter button on your iPhone? You are now one step close to the real digital camera experience! Isn't that awesome?