If like me you use a Mac computer and are using the High Sierra OS then if you want to upgrade your camera you will need this supplemental driver from Sony:
This is for any Sony camera that is upgraded via a direct USB connection between the computer and the camera, so that includes cameras like the A7s, A7r, A6300 and the rest of the Sony Alpha series. It is also for many of the PXW video cameras including the PXW-FS5. You don’t need it for cameras like the PMW-F55 or PXW-FS7 where the update is done by placing the upgrade file on an SD card.
Without this driver the upgrade software will install and all appears to be working OK. Except you can’t get a good USB connection between the camera and the mac computer and the upgrade will fail.