Android phones are not eligible to receive the latest version after they turn two years old. In this case, Nougat can be installed on these “forgotten” Android phones using custom ROMs, which offer the same features and other exclusive features.
CyanogenMod is a group of developers that bring builds to devices that will never receive Android updates from their manufacturers, or which will ne updated in the far future and their owners lost their patience and no longer want to wait until that will happen.
So, the latest CyanogenMod version 14.1, which is based on Android 7.1 Nougat, can be installed on a variety of devices.
The devices that support CyanogenMod 14.1 include: the Google Nexus 5, Moto X Pure Edition, Nextbit Robin, LG G Pad 7.0 LTE, Oppo R5, Oppo R7 Plus, LG G4, Nexus 6P, the first gen Moto G, and many more. This version is the final build, which means that it may have bugs that affect the functionality of the camera, radio or other parts of the device, and the developers are continuously working on fixing these issues, so they release updates almost every day.
If you own any of the aforementioned devices and want to give CyanogenMod 14.1 a try, then you will download the build from here, but you will need to be careful and follow the steps correctly, because if you don’t, you could risk bricking your device.
First of all, you will need to root your device, backup important data and charge the battery of your phone up to at least 80 percent. After downloading the CyanogenMod 14.1 Nougat ROM and GApps zip files to your PC, use a USB cable to copy them to your phone, then turn off the phone and unplug it from PC. Boot it into Recovery (make sure that you have CWM or TWRP), wipe data factory, then cache partition, Dalvik cache and finally, format the System partition. First, you will have to flash the CM14.1 ROM zip from device, then reboot into recovery and flash the Google Apps package.
If you don’t know how to do that, on the Cyanogen website are explained all steps that you must take in order to successfully install Nougat on your supported device.