Unfortunately, I do not have version history. That would be nice to have in the Parity Check History. But, I usually update fairly shortly after an update is released, with the exception of 6.7. That one took me a while, IIRC. I was using "tuned" settings, but reverted to defaults with 6.8.
For a couple of years, I have had the same size array: 2 x Parity + 13 x Data. All HGST 8TB HDN728080ALE604.