It has been a year since calibre 1.0 and lots has changed in calibre-land. The biggest new feature is an e-book editor, capable of editing ebooks in both the EPUB and AZW3 (Kindle) formats. Click on the items in the list below to learn more about each new feature.
Note that because of the move to Qt 5, calibre no longer supports either Windows XP or versions of OS X older than 10.7 (Lion). If you are using either of these operating systems, you should stay with calibre 1.48
Calibre Project: http://calibre-ebook.com/new-in/eleven