No. The OPPO F3 Plus did receive an official Android 8.1 update. Do not flash F3 ROMs on different models. Check your exact model number under Settings > About Phone.
To download and install the Android 8 update on your Oppo F3, follow these steps: oppo f3 android 8 update download
The situation was further complicated by Oppo’s software strategy at the time. The company was transitioning from ColorOS 3.0 to ColorOS 5.0 (which was based on Android 8.1). In many regions, Oppo seemingly skipped the Android 7.0 Nougat iteration entirely for the F3, attempting to jump straight to Oreo. However, the implementation was spotty. Many users who successfully updated found that while the Android version number changed, the user interface remained heavily locked down. The much-vaunted "Project Treble" benefits were often neutered by Oppo's proprietary modifications, meaning the update did little to solve the underlying fragmentation issues. Check your exact model number under Settings >
If available, download the firmware (.zip) to your phone's storage. Power off the phone, then hold Power + Volume Down to enter Recovery Mode. In many regions, Oppo seemingly skipped the Android 7
The device is now considered "End of Life" by OPPO, meaning no further official Android version upgrades or security patches will be released. Why There is No Android 8.0 Download
If you check for updates in your settings, you will likely see "Your device is up to date" even if you are on an older Android version. Because Oppo does not host public archives of older firmware on a user-friendly website, obtaining the official Android 8 file can be difficult.