Around 665MB in size, the update brings OS-level changes introduced in Android 7.1.2 (mostly minor stuff) and October Android security patch. Additionally, the update will also improve the system stability and packs UI enhancements.
To manually look for the update, go to Settings > System > System updates. If you have already updated your Nokia 6 to Android 7.1.2, do let know about the experience in the comments.
To remind you, all Nokia Android smartphones are scheduled to get the Android 8.0 Oreo updates before the end of 2017. The phones will also get the Android P update when it is released the next year.
Nokia 8 update:
Available OTA, the update is 293MB in size. (via)
