When it was published there was nothing in the score which said that Fitzhagen had made lots of changes. It was not until about 70 years later that people realized that Tchaikovsky’s original version had been different. Some cellists, such as Steven Isserlis, now choose to play Tchaikovsky’s original version. However, most cellists still prefer to play Fitzhagen’s version. It is hard to tell which one Tchaikovsky would have preferred. Maybe he let it be printed because he realized that Fitzhagen had improved it. We cannot tell. Musicians still argue about which version ought to be played.