The Document Foundation will be releasing LibreOffice 4.0 in the beginning of February. It is a big and important release for us, and a major symbolic milestone. We have received questions and comments, however, that were basically about our reasons to change the major number, from the 3.x to the 4.x . I believe it’s important to explain why we are doing this, and what the 4.0 release is all about.

The first place you should go before the release date is the release notes on our wiki. They are the most detailed and human readable page you can check at this stage. As you can see there are quite a lot of new features and bugfixes that come with this release, but there are also important elements that one may miss by just looking at the least of items there. Among these ones two are of strategic importance:

Major changes in the API: They are listed in this section, but what this really means is that it is the most important API cleanup that has ever occured since the beginning of… OpenOffice.org 1.x . This will allow, with time, for the introduction of deeper changes and a more powerful API. But it also means that, while the API is becoming more powerful and easier to tap into, new possibilities for extension developers will rise, with its set of changes and incompatibilities. On a more abstract level, these changes also mark a more radical departure from the OpenOffice.org codebase, and it is now becoming quite difficult to just assume that because OpenOffice.org, Apache OpenOffice behave in one specific way LibreOffice would do just the same. Of course the API changes do not make the whole work themselves, but the work we started with the 3.4 branch is paying off: LibreOffice 4.0 is becoming a different animal, and that comes with its own distinct advantages while clearly showing our ability as a community to innovate and move forward.

The rebase “for one very, very last time” on the Apache OpenOffice codebase is enabling Libreoffice to have a very clear and clean story on licensing. Essentially The Document Foundation had to use the license from its upstream, aka OpenOffice.org. This license, the LGPL v3 is a very good license, but it is neither evolutive nor exactly the one(s) we wanted. We were thus left in the awkward position to use the LGPL code and ask for any new contribution to use the GPL v3+ and the MPL licenses. The GPLv3+ is the standard Free Software License, but if you notice the “+”, it also lets the code evolve with the license (to the v4, or v5 for instance). The MPL (Mozilla Public License) is a nifty copyleft and Free Software license that has two big advantages: anything coming from the Apache-licensed code can be turned automatically into MPL licensed code; its second benefit is that this license enables us to upload LibreOffice on commercial App Stores such as the Apple App Store and Google Play, and as you may have heard this is quite important since we are developing a tablet version of LibreOffice (alongside specific tools such as the remote control for Impress on Android). Now because of all this, using the codebase that exists at the Apache Software Foundation and relicensing it under a MPL license brings us real benefits but also creates a very clean and clear licensing scheme.

These two major changes -there are others of course- make this release quite exceptional. In a sense, the 4.0 is actually an existential release, as it marks the departure from the past, and a major change in our licensing . It is also a release that is the result of the work and contribution of a very large community of developers, localizers, QA testers, marketers, documentation writers, designers, and the end result, being more than the sum of all the contributions, will be a hallmark in community developed software. The 4.0 is not just an update, it represents a deep change for LibreOffice and enables us to come closer to fulfilling our mission: to create the tools for knowledge and the instruments of freedom.