Kw88 pro bluetooth calling

i had wrong firmware on my watch and it bricked,
but i unbricked it with KW88PRO V1.3 20180713.
now how can i use bluetooth calling? i really want it. And i want to know that my version is best (maybe not) then what version is best to use? what is difference with NHH version?

Usually different firmware are for different screen hardware.
About Bluetooth call, is it supported ? Only some Android 5.1 were having this feature.

then, can i make reset an flash NHH version?