I have been reading a lot about updating batteries . How do you accutly do this? do you have to do multiple updates with the drone if you have more then one battery? can somone please advice. Thank you for your help and support.. have a great flying day!!!

If you have multiple batteries, and upgrade is needed, you need put the battery into the drone one by one to finish the upgrading.

hdlou94
As DJI-Natalia said, you will need to put each one into the quad and start the app.  It will tell you something like unmatched firmware, please update (or something like that, I can't remember).  This will pop up when you are on the main page, its the page were you can go to your flights, or chose which quad you are flying or the editor, etc.  This is the page that will show you if the battery's need updating and you can do it from this page.
I hope I explained this well enough for you.  Let us know if you got it to work.

Just to clarify all of the above, battery firmware is applied as part of a craft firmware update. I don't recall that all craft updates require to update the battery, however. You'll know when it is, when the two middle battery LEDs light up with one flashing - that is an indication of battery reprogramming.

If you're using Assistant 2 to apply the craft firmware (which I'd always recommend over using the RC/app as that's reliant on a good WiFi connection), once the update is complete, power down the craft, swap batteries, power the craft up again, and refresh the firmware to same level. Do that for each battery you have.

Everyone's hit the nail on the head thus far. Please let us know if you're incurring any issues when attempting to update yourself.

Thank you all, i will try this tonight and see what happens, but where do i find the update for batteries if i already did the update two days ago?

Another option is to purchase the DJI battery charging hub. For the Phantom 4 series (I have the P4P) the hub has a micro USB port designed for firmware updates on the batteries. You can update all three high capacity batteries together using this feature.