You can check your version to see if "btn sound" has been change to "key tone". If it's "key tone" it's more likely a newer fw update.
I know that goodvibes just received another Rocoo. In this unit there's yet another fw, presumable newer, with the "btn sound" changed to "key tone".
With this version he doesn't experience the change in sound when turning on/off the "key tone".
When I used the dynamic fw on the Studio there was a change in sound as well, when turning the "btn sound" on/off.
With the Studio "original fw" with "key tone" instead of "btn sound" I now hear no difference. Never bothered to check it before now.
Therefore I believe that the "original fw" must be a later release, because it does make some kind of sense in all this fw confusion
Even if the "original firmware" is a slightly newer fw, doesn't mean it is going to sound better than the dynamic (that many do prefer, but some doesn't), but the
"key tone" thing seems to be fixed in this release and it bothered me a lot that it sounded different when turning it on/off.