Got the clear C8 with the new firmware on Bangood here and have it on the first setting where the eighth click will flash out the battery voltage. Worked fine for a few months and now it always reads 3V when actual voltage is 4.02V. Tried several times and still flashes only three times instead of four and also doubled checked on two DMM where both read 4.02V.
Thanks for the link!
no problem, hope you’ll enjoy your light 
Yeah, it's a great little light. I just assumed the battery readout would be like my Q8. Goes to show you to "never assume anything".