I have an 8 drive raid 6 array full of seagate NAS 4tb drives on my areca raid controller. They are all firmware version SC43. It's filling up again so I ordered a 9th drive for the array. It came with firmware version SC44. Seagate support said it's impossible to downgrade the new drive's firmware to SC43, and I remember reading somewhere that you're supposed to keep the firmware version consistent, though in the past I've had all sorts of random drives in a hardware raid without too many problems.
Why do you want the firmware version to be the same? What issues can arise from having this drive as a new FW version?
Why do you want the firmware version to be the same? What issues can arise from having this drive as a new FW version?