One the most anticipated upgrade of the KDE 4 series (KDE 4.3) has begun shipping, after the KDE project spent six months in development in order to 'greatly improve' the overall user experience of the open source desktop environment.

KDE 4.3 (codenamed "Caizen") has had the goal "polish, polish, polish," according to its developers, who were scorned for beginning the KDE 4 series with a basic 4.0 release that did not have all the features of the 3.5.x predecessors.

With this release being the fourth of the KDE 4 series, the momentum and pace of development is definitely increasing with some 2000 feature requests implemented in the past six months alone.

Other statistics from development team indicate 10,000 bugs fixed and approximately 63,000 changes committed by nearly 700 contributors since 4.2.

All that has led to 4.3 being one of the most anticipated free software releases this year.

Technical highlights of 4.3 include better integration between Plasma, KDE's desktop interface and KWin, the window and compositing manager which allows theme sharing and it is also possible to have separate sets of Plasma widgets and wallpapers on each virtual desktop.

KDE's graphic design team has also created a new Air theme for the release.

"It is much lighter than the [previous default] Oxygen theme, which is still available through the Desktop Settings dialog," according to KDE.

A new "tree view" in KDE's System Settings which is intended to appeal more to people still using KControl in KDE 3.

Dolphin, KDE's file manager, now shows previews of images contained in a directory as an overlay for the directory icon and hovering over it enables a slideshow of the images in the directory.

For Plasma applet developers, there is a geolocation plug-in that makes it possible to query location. This is used in the OpenDesktop applet to show people near you.

Also, the new KDE PolicyKit library provides allows applications to authorise actions based on profiles.

In addition to underlying technology enhancements, KDE 4.3 also adds a number of new applications for networking, multimedia, graphics, personal information management, education, utilities and games.

Akonadi, a PIM storage service, has been deemed "ready for more widespread usage" and the is now a DataEngine for plasma and developers are encouraged to use it for access to, or storage of, chat logs, email, blogs, contacts, or any other kind of personal data.

To celebrate the release the KDE project has also created a new "Microblogging Lifestream" at Buzz.kde.org to aggregate developer updates from social networks like Twitter, Identi.ca, YouTube and Picasa.

The KDE 4.3.0 release will be followed by monthly bug fix and translation updates with the next feature release, KDE 4.4.0 due in January 2010.