Nokia 8 Sirocco User Guide

Tap Settings > System > System updates > Check for update to check if updates are available.

When your phone notifies you that an update is available, just follow the instructions shown on the screen.

Warning: If you install a software update, you cannot use the device, even to make emergency calls, until the installation is completed and the device is restarted.

Before starting the update, connect a charger or make sure the device battery has enough power, and connect to Wi-Fi, as the update packages may use up a lot of mobile data.