I don't know about legally but I would certainly think that morally you do..but it just usually is so icky what they do when they change things..it's not that I don't think they have a right to do it..it's just that they generally can't see how they made it worse..I guess there are situations where someone has improved on something..like come to your life like a warrior don't let it bore ya...that should be changed..most everyone would agree...mg