From the changelog:
New driver for the Kobo featuring closer integration with the device.
Support for the Dell Streak, Eken Android tablet and the Astak Mentor EB600
New series type custom column
Add option in Send to device menu to connect to iTunes without any iDevice (experimental)
iPad driver: Make setting iTunes Category from series optional. News download now optimizations for iPad output.
Add option to disable book cover animation
Edit meta information dialog: Remember last used size and splitter position.
Metadata download: If any results have a published date, ensure they all do
SONY driver: Add a preference setting in Preferences->Add/Save->Send to device to control how collections are managed on the device by calibre
Metadata download: Filter out non book results. Also sort results by availability of covers for the isbn
Bulk editing for device collections in the device view via the context menu
When converting books using the calibre GUI, set the language of the output book to be the same as the language of the User Interface, instead of undefined. Fixes use of dictionary in iBooks
PDF Output: Fix setting top/bottom margins has no effect
Conversion pipeline: Fix typo causing remove footer regex to always fail
Handle device being yanked with queued device jobs gracefully
Conversion pipeline: Handle deeply nested XML structures
Conversion pipeline: Fix handling of lists with a specified left margin
Restore workaround for ADE buggy rendering of anchors as links. However, make it overridable by extra CSS
Fix LibraryThing metadata download plugin
Fix multiple ratings displayed in Tag Browser for some legacy databases
Fix invocation of postprocess file type plugins plugins
HTML Input: Handle @import directives in linked css files.
HTML Input: Handle absolute paths in resource links on windows correctly.
E-book viewer: Handle font-face rules specify multiple families to be substituted
Cover browser: Set aspect ratio of covers to 3:4 instead of 2:3. Crop rather than distort covers whose aspect ratio is different from this. Antialias the rendering of the central cover
Reset Tag browser if the text in the search box is edited
Fix detection of SD card in Samsung Galaxy windows driver