Why would you have to update your firmware?
Once all the bugs are worked out of something, and there are literally billions of trouble-free hours with it, what company would be stupid enough to make changes to the firmware just for the sake of "updating" it?
Or, to look at it from a different perspective, why would LSI invest any more time in a ten year old product? It works fine, the firmware developers have probably moved on to newer and greener pastures, and now that LSI has been sold to Broadcom has been sold to Avago, what motivation does Avago have for spending the money to make updates to a product they don't sell in any meaningful quantity?
I expect that there could be another firmware version or two if it ever comes out that there is some critical edge case bug. Otherwise, I wouldn't hold my breath. We sometimes luck out in this business and get a perfect chipset or perfect driver or perfect firmware. :)