I hate to be the bearer of bad news, but each battery has its own circuitry and its own firmware that occasionally needs updated. Those battery firmware updates are independent of RC and AC (drone) firmware updates, though they're often released simultaneously.
The latest AC firmware update (the one in the thread title) was accompanied by a battery firmware update. When you apply the AC firmware update, the firmware in the battery that happens to be powering the drone also gets updated. You then need to shut down the drone, insert another battery, power up the drone again, and update that battery's firmware. Repeat this process for all batteries in your inventory to update their firmware. If you don't update the firmware on all your batteries at the same time, you'll be required to the next time you use each battery.
Larry