@Nickyb65 ,the last up date mentioned by
@Hands Down above, did indeed have a battery update as part of it ,and yes he is correct each battery has to be updated, the one in the drone during the update gets done during the initial update ,then just remove it after switching off the drone only ,put in a new battery turn on the drone click to start update and then it will go to about 75% of the update and then let it run to the 100% update finished ,switch off the drone and do the same thing for any other batteries you may have,till they are all done
have a small fan blowing over the drone during the process to help keep it cool