With the release of Android 8.0 Oreo, Google also pushed Android Oreo source code to AOSP.
We all know that most of the devices won't be getting Official Android 8.0 Oreo update, but with Android Oreo AOSP code base, developers will be able develop custom ROMs for the Android devices based on Google's latest OS.
The developer is actively working to fix all the bugs present and will release the Custom Rom soon.
You'll need to Root and Install TWRP Custom Recovery in-order to Install the AOSP Android 8.0 Oreo Rom on Xiaomi Mi 3W.
That said, we'll notify you once developer releases the Android Oreo Rom. Stay tuned to our Facebook and Twitter page to get the first News.