Project Treble makes the OTAs modular allowing manufacturers to update their devices faster and longer.
Google has already updated their 2016 Pixel Smartphones with Treble, but HMD contradicts saying that Google only supports Project Treble on phones launching with Android 8.0 Oreo.
"Nokia 8 was launched with Android 7.0 Nougat™ however we recently upgraded this device to Android 8.0 Oreo™. Unfortunately Google only supports Project Treble on phones launching on Android 8.0 Oreo™, not phones upgrading to their software.
HMD is fully committed to implementing Project Treble on all new Android Oreo products in the near future and we apologise for any disappointment this may cause."