This new version brings 4 new major features:
Management of hierarchy of objects (Organizations, Locations, Groups)
Performance enhancements: don’t be afraid to manipulate hundreds if not thousands of objects with iTop, through the new "paginated" display.
Support of Central Authentication Service (JA-SIG CAS) for a seamless integration with portal applications.
Japanese localization: Thanks to Tadashi Kaneda, iTop is now available in Japanese !
Plus quite a few enhancements, like:
Drill-down capability on charts
Easy ’one-click’ upload of attachments on tickets
’Class’ keyword in the global search: for a fast search search only on the given class of objects, by typing "class:search-string" (e.g. "server:demo")
Productivity enhancements: faster access to the most common actions, buttons at the top of the page to avoid scrolling...
And many more (including bug fixes) as listed in the release note.