https://9to5google.com/2019/07/23/nvidia-shield-tv-android-pie/
I don't see how they could do it for one and not both. 2015 and 2017 Shield Pro are identical, so unless they want to do it for 2017 and Pro only (which would really suck, and I can't see nvidia doing that), it'll have to be for all.
What are the new features? The three articles I read about this today didn't mention. Assuming they aren't noteworthy?
Will the Android TV UI render in native 4K resolution or will we be presented at 1080p blurriness?
I'm just gonna say I have the 2015 model 🙃