Ultimately, the Oppo F3 Android 8.0 update download represents a failed promise for many. While the update eventually trickled out to some regions, many users found themselves stuck on older software or facing bugs in the new build that were never patched. By the time Android 9.0 Pie became the standard, the Oppo F3 was effectively abandoned by the manufacturer.
If you are performing a manual installation of the official software: OPPO System Upgrade Tool | OPPO Global oppo f3 android 8 update download