I’ll check when I get in Bob. Although I have never had a drive fail since install 16 months ago. So don’t actually know if it works :-/
I have always updated the firmware drivers without issue if following the correct procedure.. unhook drives etc.
One error that may now be gone that I had with the initial firmware was if you do a software update (sometimes) or use SuperDuper to clone the OSX install for a failover disk then the raid gets messed up so we turn it off and disconnect before the above.
Simon