Nokia has released Android Oreo 8.1 recently to its Nokia 5 and Nokia 6 smartphones. Nokia 3 was running on Android Nougat. Juho Sarvikas Chief Product officer HMD has confirmed that Android Oreo 8.0 rollout has been started to Nokia 3 through his twitter account.
— Juho Sarvikas (@sarvikas) April 11, 2018
Nokia 3’s Oreo update has been in beta stage for long time and now the stable version has been rolled out through an OTA. Still Nokia 2 is the only phone running on Android Nougat.