Previously, we have introduced Asus ZenFone 3 (v14.2015.1701.8) Nougat OTA Update, but if you have problem installing the OTA update (like network issues), you can download and install the update manually.Check out the below guide to know how to update Zenfone 3 ZE520KL and Zenfone 3 ZE552KL to Android 7.0 Nougat with official firmware.
In addition, the update removes some existing Zenfone features, such as Share Link, because of incompatibility with Android Nougat. Check out complete changelog of Android Nougat at this page.
Note: If you do not received the update notification yet, then go to Settings > About > System Update > and check for update manually. Users who prefer manual installation, head over to the below guide.
How to Update Asus Zenfone 3 to Android Nougat Manually
Disclaimer: Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components.
Note: Before proceeding with below steps, back up every data you have on the phone. Also, make sure at least 1.5GB free space remaining on the SD card.
Download: Download Nougat update for Zenfone 3 ZE520KL from here and for Zenfone 3 ZE552K from here.
1. Rename the downloaded firmware file to ‘update.zip’ and save it on your phone.
2. Boot your phone into recovery mode (Switch off the phone and turn on by pressing Power + Volume Up buttons together).
3. In recovery, choose Apply update from sd card and then select the update.zip file.
4. After completing the installation, reboot your phone.
Enjoy Android Nougat, new ZenUI and other new features. Leave your views in the comment section below (Source)