Nikon has updated the firmware to address a EN-EL14a battery issue.
From Nikon:
Modifications enabled with this firmware upgrade
Remaining battery charge is now accurately detected for Rechargeable Li-ion Battery EN-EL14a. By upgrading firmware to [current version], EN-EL14a performance is maximized so that more images can be captured (battery performance) than when an EN-EL14 is used. With firmware [previous firmware version] and earlier, the number of images that can be captured (battery performance) when an EN-EL14a is used is less than when an EN-EL14 is used.
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