What is your current and Android security patch date ? (Found in Settings > About Phone).
The MediaTek chipset in the F3 is not well-supported for custom software development.
Better RAM management and faster app loading times due to optimized ColorOS 5.0 architecture. oppo f3 android 8 update download
Before looking into unofficial options, ensure your phone is completely up to date with the latest available factory software. To check your status: Open the application.
The Oppo F3 Android 8 update was released in 2018, and it's based on ColorOS 5.1, which is Oppo's custom skin on top of Android 8.1 (Oreo). The update brings several new features, including: What is your current and Android security patch date
If you click on the first Google result promising a direct download of “Firmware OPPO F3 Android 8.0,” you risk:
on the official OPPO System Upgrade Tool for Android 8 on this specific model. 🛠️ How to Get Android 8 on Oppo F3 Better RAM management and faster app loading times
Unlocking your bootloader and flashing custom software will permanently void any remaining manufacturer warranty.