Found this out by accident, was trying to access the ‘engineering mode’ but it doesn’t seem to exist on my light, instead it has a moonlight group brightness adjustment mode of sorts.
First of all you need to isolate the threads on the body, with the light off, press and hold the button and tighten the head. Previously this would enter engineering mode and flash some lights, but on my model it just light up a dim light. Pressing the button will cycle between 32(I think) different brightness level with the first 13-15 brightness level being too dim to see. After selecting a certain brightness level you like, either press and hold or double tap the button to return to normal mode again and you will notice the brightness of the Moonlight group will now be different.
I wish manker can put this in their official documentation as the first time I entered this mode, it was by accident which made my moonlight mode so dim it is completely unusable. I thought it was broken and replaced my unit with the dealer, that was when we started researching into the engineering mode and trying it out and we found something else instead.
I bought my light yesterday so this should be one of the latest batch. On the pcb underneath the positive terminal the marking days ‘MANKER DL124Vsonix’