Since Oppo uses a specific system for software updates and users often have different reasons for seeking firmware (updating vs. fixing a bricked phone), I have broken this guide down into the most common needs.
There are two primary trusted sources in the Android community: firmware oppo a78 4g
You can check for and install firmware directly on your device: System Update: Navigate to Settings > About device > ColorOS version to check for the latest official OTA (Over-The-Air) update. Trial/Beta Versions: Since Oppo uses a specific system for software