Just a month ago Moto Z updated to Android 7.0 Nougat os, but now this handset receives another software update. The changelog mentions it will fix low notification sound issue that faced by users after upgraded to nougat os. The size of this update comes in large size 540MB. It will also update build version to NPL25.86-17-3 (earlier build version is NPL25.86-15).

This update will not upgrade the android version it will stays in 7.0.  As usual the update rolled out for Moto Z users through regular OTA update. If your handset is eligible you will receive the software update notification. You can check this bug fix update from Settings > About phone > System updates. If it is available for you device download the update with WiFi network and also keep your battery above 70 percentage.