Micropython Firmware

Silly question - on the Ringo Python gitpage is says to
Remember to flash the provided “ESP32_c.bin” custom firmware as it contains all the dependencies required for Ringo phone to work with MicroPython
However, in the zip file there is a file called ESP.32_ringo.bin
Should I be using ESP32_c.bin or ESP.32_ringo.bin and if it is the former, where can I get the file