In those days, when Android phones were still popular, we would have looked for the CM package of their mobile phones. Cm is short for CyanogenMod, a third-party customized brush pack that is almost the same age as Android. Later, CyanogenMod evolved into lineageos, so lineageos is still the most popular third-party Android ROM.
the first generation of Yijia mobile phone was released in 2014. At that time, it was also a little prince in the mobile phone circle. Due to its good hardware performance, developers were keen on adapting this mobile phone. Six years later, no one expected to get Android 10 system updates with a mobile phone. It should be noted that the official system update of the first generation plus mobile phone was in 2016.