You may have heard a great deal (or none at all) about Project Treble. The reason that it is sort of a big deal is that it is Android's ongoing solution for the problem that Android has faced since the very early days of its existence: fragmentation - this happens when the latest version of Android is updated and OEMs (namely, Samsung) take a long time to update its heavily skinned devices to the latest version of Android. By contrast, iOS does not have this issue since Apple controls both the hardware and software of the iPhone.
Treble sought out to help end fragmentation (or at least make updates much easier and quicker for OEMs) by taking the single OS framework and dividing it up into two separate ones: one that contains the core Android OS and the other would contain the OEM's UI modifications. Separating the two would theoretically make updates quicker.
XDA-Developers released a list of devices that have been officially updated by the manufacturer to support Treble. Since all smartphones that come with Oreo out of the box are required to support Treble, this list won't include all those devices.
Again, these are devices that didn't launch with Oreo, but have been updated to support Treble. Huawei/Honor has updated many of its devices while both Essential and Razer decided to update their only devices to set up their customer for these quick updates.
Project Treble has also started a new chapter in the development of aftermarket ROMs over at XDA. Treble has made it easier to port stock Android images to a device that comes with an OEM-modified Android skin.
Check out the full list of devices over at the source link, which include devices that were unofficially updated with Project Treble.
check whether your device support treble by using the below 'adb' command: 'adb shell getprop ro.treble.enabled'
it is nokia 7 plus support project treble..?