Remember the Android 7.0 feature Night Mode? This was supposed to give Android users the ability to remove blue light on the display, giving the screen an amber look. Without the blue light coming from the screen, users might find it easier to fall asleep since that light can negatively impact users' life cycles. In addition, removing the blue light makes the screen "warmer," and that also will help users get to sleep without a problem.
The developer preview for Android 7.0 contained Night Mode, which was hidden by the time Nougat was launched to the public. The similar Night Light runs on both Pixel models, which employ Android 7.1. But that is only because the Pixel models have the drivers necessary to run it. Other models powered by Android 7.1 will not offer Night Light. And even certain third party apps like Night Mode Enabler, which was supposed to reveal the feature on phones running Android 7.0, are disabled on Android 7.1.
However, it would appear that the recently unveiled HTC U Ultra will offer Night Mode right out of the box. A video released by HTC shows how U Ultra users (love that alliteration) can enable the feature. Scrolling down on the notification bar will allow them to tap on the icon; if you look closely at the video, the screen turn amber instantly. Users can also customize Night Move to turn on at a certain time and also turn off at a certain time. To do that, go to Settings > Display, gestures and buttons and click on Night Mode.