Why, yes it has changed. The 'bible' has been translated, and mistranslated for one. And second of all, what constitutes the 'bible' has changed. Before a certain timeframe, there was no set canon about what constituted the Bible, or what constituted the tankah.
The text of Isaiah might not have changed all that much. What constitutes the Tankah has. Also, what is considered part of CHristian scriptures has changed. The council of Nicea formalised what they thought should be considered scripture. The church in rome also went on a program to destroy as much 'competing' scripture as they could.