Oh dear if your the owner of a Nikon D3100, D3200, D5100, D5200 and P7700 camera and you have some third-party batteries you might want to hold off on the upgrade. Nikon Rumors broke the story last night that, the firmware upgrade which was meant to maximise battery performance and allow the camera to accurately tell you how much charge you have left has had an undesirable side-effect.
It also makes it impossible to use Nikon batteries in third-party battery grips. It’s unknown at this time, if this was an unintentional or intentional side-effect. If it was intentional I think it would have been better for Nikon to disclose this information.
Another problem is that if you have upgraded their firmware there is no way (at the moment) to roll it back a version. Nikon don’t provide downloads for previous versions.
(Via Nikon Rumors)