Apparently Nokia's update delivery infrastructure is gutless and that's why many users get ridiculously late updates (they have to dribble them out). Neither of my phones has received the Android 8 final, though it was released on he 31st of January. One of them is on the Oreo Beta (why the hell didn't they prioritize beta testers for the stable release?) with 5th December 2017 security patch and the other is on Nougat with the 1st January 2018 security patch. Another reason why I hate these phones.
If anyone wants to buy a barely used Nokia 6, let me know. I think it's time I got rid of at least one of these. Full disclosure: worst phone I've ever owned.
You can install updates manually through recovery. There are direct download links to Google's OTA servers on XDA.