After reading a horror story about an i2 falling from they sky because it did a firmware update mid flight possibly related to new batteries, I put my new set in and... firmware update required (inconsistent firmware). It then downloaded and installed. I then put my two other sets in and it did exactly the same so presumably did have a battery firmware update to apply.
Can't see the battery firmware versions but the others are:
Aircraft 01.00.0135
Remote controller 01.00.0050
Camera (x4s) 01.02.14.43