Nokia has been releasing the Android 10 update for a number of devices over the last few week, the latest one to get the update is the Nokia 8 Sirocco.
Thew news of the update was announced on Twitter by Juho Sarvikas and the update is being released as an over the air update.
— Juho Sarvikas (@sarvikas) April 15, 2020
The Android 10 update should be available for your Nokia 8 Sirocco as of now, you can check to see if it is available from the settings menu.
Source Juho Sarvikas