Everyone complaining about a yellowish tint to the display should read up on exposure to blue light being linked to causing macular degeneration (degeneration of the iris) (aka going blind).
Apple is doing you a favor tinting these screens intentionally away from blue. They are well aware of the relationship of blue light and MG.
Personally I keep my older phone with Night Shift permanently on all the time. The slider control almost to halfway. At first when turning it on, the screen color seems very warm, but once your eyes adjust to it in a short while, it looks natural.
Then when you turn Night Shift off — the screen looks WAY too blue... because you've gotten used to the warmer color.
Everyone do your retinas a favor and KEEP TRUE TONE ON. Turning it off is more damaging to the eyes.
Apple may have obfuscated the real reason why they're warming up the display color, telling everyone it's done to create a more natural look, when in reality they're probably yellowing the screens to minimize damaging millions of people's eyes.