Insufficient storage or weak Wi-Fi. Fix: Free at least 3GB of internal space and use a 5GHz Wi-Fi connection.
Visit the Oppo Support Page and select "F Series" then "F3" to download the latest firmware package (ZIP file). oppo f3 android 7 update download
OPPO rolls updates in phases. If your IMEI hasn't been activated, you may see "Your system is up to date" on Android 6.0. In that case, proceed to Method 2. Insufficient storage or weak Wi-Fi
Before diving into the update details, here are the key specifications of the Oppo F3: oppo f3 android 7 update download