I am testing the new power circuit for v4, this black PCB are from PCBway and that helped me to quickly test out the new changes. The production was fast and i got the PCB within 3 days.
I had to make the v4 because of 2 reasons, the power supply is not enough and a lot of tiny mistake i made on the scolding pads. now those pads are bigger and easy to solder.
But V4 and v3 are not compatibles in the size so there is no drop in replacements.