Whoscall setting on OPPO ColorOS 3.1 and 3.2 (R11, R11s, A75, A75s, A73)

Due to the varying optimization software used by different brands, Whoscall may not work normally on some devices. We will later get into the customization needed for each individual brand in order to fully utilize Whoscall. Today, we will focus on OPPO ColorOS 3.1. Please take note of the following instructions and set your device accordingly.