There are some small changes to columns, but no new tables:
* qa_posts has separate upvotes/downvotes instead of current votes column.
* qa_userpoints has new upvoteds/downvoteds columns.
* qa_posts has a new column lastuserid and modifies the definition for updated.
* qa_contentwords has new columns: type and questionid.
But please don't do this to your database manually. Q2A will take care of all the changes using ALTER TABLE when you first run the new version.