Originally Android 5.1 (Lollipop) with ColorOS 3.0; upgradable to Android 6.0 (Marshmallow) Official Support:
The correct is designed specifically for the A1601 global edition. It manages everything from camera drivers to battery optimization and network radios (GSM/LTE). Oppo F1s Mt6755 Firmware
The Oppo F1s MT6755 firmware is based on the Android 5.1 (Lollipop) operating system. However, Oppo has released updates to Android 6.0 (Marshmallow) and later versions. Originally Android 5