A little forum search and I found the updates at http://www.piano-schmitz.de/download/download.htm .
You will need four floppies as there are four seperate downloads.
A quote from Technicsplayer "just switch on with the first disk of the pair in the drive while holding down panel memories 1 to 4. For the rest just follow the instructions in the screen - be SURE to do a checksum on ALL disk BEFORE attempting the upgrade proper."
Good luck
Keith