Thanks for the replies folks 
By "upgrade", do you mean connecting (the receiver in this case) & doing the keyboard identification process?
If so, then yes I have. However, it isn't an Apple keyboard, it's a Logitech one (if that counts for anything...which I guess it certainly might).
PZ.
I think Thecrow mixed wireless keyboards with bluetooth one, which works fine under MorphOS but they have to be identified under osx first.