The changes to the second edition include a large number of fixes to the exercises and solutions, corrections from bug reports, and any updates necessary for Scala version 2.11. Some examples are replaced or improved, and much of the book’s prose is improved.
If you bought the first edition eBook, you automatically get an update to the second edition. Unfortunately, the number of changes to the first edition print book are just too comprehensive to summarize in a document.
Currently, only the eBook is available but in the coming months the new edition will become available in print form as well.