Updates are rolling out fast of late with HMD and Now the Nokia 5 and 6 are legible for Android Oreo in betalabs but you need to sign up for this and you will be notifed by email, Still waiting on my Nokia 5 to get it and also the latest update for the flagship Nokia 8.
The DECEMBER update has just hit my Nokia 3 so go and check your device to see if its available and rememeber updates are phased out but do keep checking in. If you need to check you just go to Settings – About – System updates and you will be told then if its available but try two or three times as this has happened to me before and the update came through. This update is 466 MB