I got the 2.6 upgrade on 2 of my 3. Batterys,my last one has firmware 2.0 in it,the two 2.6 batterys have an auto discharge option and my 2.0 doesnt,why is this necessary? I cannot upgrade the 2.0 battery, I currently have no swelling, I contacted dji and they claim that 2.0 battery doesn't need...