Android 7.0 Nougat brought a range of new features to the table, including a new special mode, called Night Mode (Night Light for the Pixel and Pixel XL), which adjusts display settings to reduce eye strain in low light settings. Unfortunately, in the Android 7.1 developer preview the feature has been removed, although it is still available for the Pixel phones on the official version of Android 7.1. Users who enjoyed Night Mode may be disappointed by this decision, but thankfully, with the help of some modifications provided by the XDA developer community, there is now a way to enable the feature once again on your Nexus 6P running the latest version of the operating system, Android 7.1.1.
As well as restoring Night mode to your device, these modifications will also add a NavBar tuner, which allows you to tweak the look and feel of your on-screen buttons, and a tinting feature, which will change the color of the notification bar and the NavBar to match the color scheme of the current app. It should be noted that these modifications may be rather complex for the average user, and if you don't feel comfortable performing advanced operations on your device, it may be a good idea to hold off on making any serious changes. With that said, if you'd like to attempt to restore Night Mode to your device, you'll need to have an unlocked bootloader. The first step is to download the required file which you can grab from the button below. Once you have chosen and downloaded the file you need, you'll need to reboot your device in recovery mode. From here, you simply need to flash the applicable .ZIP file, then reboot the device. Upon starting Android after flashing the file, if all has gone well, you will see some new options available. Night mode can be turned on by navigating to Settings > Display, and the System UI Tuner will have some new options as well.
Android is an extremely flexible mobile operating system in itself, but when the built-in options are not enough, fortunately, the developer community often creates their own modifications that give users even more control over the way their devices look and function. If you'd like to give these tweaks a try, the full detailed tutorial can be found by following the source link below.