The main feature is the native OpenDocument support. It takes a lot of courage to ditch your own file formats and jump into a new file format you don't control. And that's exactly what the KOffice developers did. Their contribution to OpenDocument is invaluable, either by contributing to the format directly, or expanding the standards for applications which do not have a OpenOffice counterpart, such as Krita, (or Gimp), KPlato, etc... The KOffice developers also found several bugs in OpenOffice OpenDocument support, bugs that can only be effectively found if you have other programs generating standards compliant OpenDocument.

In this release, Kexi, the long waited MS Access replacement, and Krita, the painting and image editing application, matured greatly, and are now competing for the best application title, in their respective classes.

Therefore, I believe that the KOffice release is excellent news, and should be celebrated.

Here are some links:

The press release.
The announcement with details on binaries, download options, libraries, etc.
The changelog

Enhanced Accessibility for Users with Disabilities

The decision of the Commonwealth of Massachussetts to base its future document format on open standards started a great debate with many different people and organization taking part. The start of it was Microsoft's assertion that programs using the OpenDocument file format could not be used by handicapped people.

The direct outcome of this debate was that OpenOffice.org, KOffice and vendors of other office software started to work hard on rectifying this situation. This version of KOffice has support for enhanced accessibility through the means of mouseless operation and text-to-speech functionality.

It is therefore our hope that KOffice can in future be used even by handicapped users, and we are very interested in feedback on this.

So, if the project appeals to you, please do try out the new stuff, and provide them feedback, especially if you are disabled. If you are not disabled, here are other areas where you can help with feedback even if you are not a coder but like me, just a happy user:

Great care has been taken to ensure interoperability with other office software that supports OpenDocument, most notably OpenOffice.org. We acknowledge, however, that the ODF support and interoperability is not yet perfect. We hope to be able to quickly identify and fix the incompatibilities that do exist in the upcoming 1.5.1 and 1.5.2 bugfix releases.

The announcement says they've doubled their development base from 15 to 30 since the last release, but the more the merrier. Here's where you find contact information. Finding bugs is part of what makes FOSS development so rapid, and we don't need to be developers to share in that part of things. If by any chance you've never done bug testing, all you do is try out the application and if anything doesn't work just right, let the developers know. In addition to disability issues, here's what they plan to work on next if you are a developer:

Regarding future development, KOffice 2.0 will be released around the turn of the year 2006/2007. It will build on the same platform as KDE 4.0, which means immediate portability to Windows and MacOS X. KOffice 2.0 will also include improved font handling, change management and improved integration.

And here's the download page. There is an alternative:

Innovative Testing Facilities with klik:

KOffice developers want to make testing as easy as possible for our users. Therefore, we offer to you an additional method to testdrive KOffice 1.5.0 which doesn't require the replacement of the last stable release on your system by current beta packages.

We teamed up with the klik developer team, who will provide up to date klik packages for all of KOffice. klik packages may be used without installation (they run, similar to Mac OS X "AppDir" bundles, from a self-contained directory tree -- but klik compresses the tree into one single file for easier handling). klik-bundles work on multiple Linux platforms without disturbing the system's native package manager (see also klik User's FAQ). A Wiki holds details about KOffice klik bundles and supported distros.

The announcement mentioned Kexi. If you're wondering what Kexi is all about, here's some info Groklaw's vruz collected for me:

Kexi is another relatively new and until now little-known application in KOffice, that has been actively developed since 2002. If you build databases for office applications regularly, Kexi is great news for you. Kexi 1.0 is the first fully-featured version of this integrated data management application in KOffice.
It can be used for creating database schemas, inserting data, performing queries, and processing data. Forms can be created to provide a custom interface to your data. All database objects -- tables, queries and forms -- are stored in the database, making it easy to share data and design.

Jaroslaw Staniek is the lead Kexi developer who has been working on Kexi full-time for three years, his work sponsored by the Polish company OpenOffice Polska, which sells a commercial version of Kexi for Windows. Even though the stable core Kexi team is small, the project receives help from a broad test base.

Here are some Kexi features that make it stand out:

• Multiple database backends: Mysql, PostgreSQL, SQLite supported (so your data is never trapped)
• RAD-style database applications development
• Support for Python and Ruby as open source scripting languages
• MS Access users migration path, MDB database tables import based upon the work of the MDB-Tools project

And it's an all-FOSS solution.

• a frame-based, full-featured word processor (KWord);
• a spreadsheet application (KSpread);
• a presentation application (KPresenter);
• a flowchart application (Kivio);
• an integrated database application (Kexi);
• a pixel based image editing and paint application (Krita);
• a vector-drawing application (Karbon14).
• a technology preview of a new project management application (KPlato).

Additionally, KOffice includes robust embeddable objects:

• report generator (Kugar)
  Note: Kugar is deprecated in this release will be replaced with another solution. It's only included since there are users that are already using it.
• full-featured charting engine (KChart)
• mathematical formula handling (KFormula)
• as well as a built-in thesaurus (KThesaurus) and support for many different file formats.