originally launched with Android 5.1 Lollipop (ColorOS 3.0). While official updates from OPPO were limited, there have been various official and unofficial methods discussed by the community to bring the device up to Android 6.0 Marshmallow Official Software Status Default Version: Most units shipped with Android 5.1. Marshmallow Update:

Gives you granular control over what data (like location or contacts) your apps can access.

Android 6.0 remains the :

Some A37f units require an unlock code from Oppo. If fastboot oem unlock fails, search XDA for "Oppo A37f bootloader unlock without code".