Trying to load older firmware into devices can be risky and damage the OS of the (keyboard). If manufacturer safeguards are not in place to automatically not allow installing older versions, then at the user's risk.

Like PC programs, upgrades will generally be no problem, while other programs will automatically remove the older version before loading the upgrade. At least you have the option of completely removing a PC program if you wanted to reinstall an older version safely.

Going to an older OS firmware sometimes may not be able to remove the conflicting info from the latest installed OS and freeze up or damage the devices OS. What would you do then? Luckily it appears the Ketron devices will allow this, but personally I wouldn't risk this on such expensive hardware.

Marcus