I am also interested in this. I have various software issues I'm hoping Oreo will iron out. Unfortunately even the beta testing is unavailable for my handset.
Both Google, third-party developers and the mobile operators need to update their apps to be Oreo compliant.
If you are facing software issues now it could be the particular app is not even fully compatible with Android 7.1 or the pure Android in Nokia phones?
I'm currently struggling with anything that connects to the phone via Bluetooth LE. Not sure if it's the phone firmware, the Android OS version, or the app developers using Samsung specific BLE hacks instead of the official API's.
Oreo is certainly not going to resolve all issues for everybody.