We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.
I am using an Oppo f3 plus smartphone and I cannot upgrade to Android 8.0, I am currently using Android 6.1
You should contact to the Oppo customer care. They will resolve your problem and suggest you better as per your cell phone and other procedure.