Next you know FW 6.2.1 only provides:
What's new for Pocket Cinema Camera 4K
Improved stability for future software updates
Nothing to do with the battery indicator. Next, BMD batteries lack the battery charge feedback pin, so battery life is limited to the default battery voltage indicator. If you use OEM Canon battery, you can get voltage and percent readings. Personally, I like Battery voltage indicator, as it gives a better indication of battery status. When you get to 7VDC, time to change the battery. Press the battery bar in the upper right hand screen to change between percent and voltage readings. The BMD batteries are not the best choice in a LP-E6 battery, but they do work OK.
Cheers