Nokia 8 (2017) is now receiving the official and stable release of Android Pie. The stable rollout is happening after a short round of beta testing which lasted for some 8 days.
— Juho Sarvikas (@sarvikas) December 19, 2018
As always, the rollout is phased. What that means is that not all regions will receive the update at the same time. Some regions will receive it immediately, while the others may extend for a few weeks. Updates in developed countries are usually a tad slower due to carrier interference.