We’re yet to get our hands on the OTA file of Xperia XZ Nougat update, but we do have a trcik for you which would get you the Nougat OTA right away.
Well, all you have to do is install this particular Android 6.0.1 Marshmallow based firmware, 39.0.A.3.30 (download link), that actually belongs to Russian users. This is a full firmware, and can be installed on any Xperia XZ, whose model no. is F8331.
The firmware come in FTF file format, and is easily installed on phone using the ever-trusted Windows software called FlashTool. You can look for videos on YouTube for help with this.
Also read: CM14.1 ROMs [CyanogenMod 14.1]
Once you have the firmware installed, setup your device, and look for the system updates under Settings. You should receive the Nougat OTA right away. It’s confirmed to be working by XZ users.
Do let us know how this works out for you.