In Hong Kong and Indonesia today, Moto Z users are in the process of receiving the update to Android 7.1.1. The phone originally shipped last year with Android 6.0 pre-installed, and was eventually updated to Android 7.0. Once the notification is received that the update has hit your Moto Z, make sure that the device is connected to a Wi-Fi or strong cellular signal before continuing with the updating process. At the same time, the battery on the phone needs to be charged to at least 50%.
If the update has not been received yet, you can try to have it sent to you manually by going to Settings …