• Can I develop closed source products with Sipdroid?
• Who are the copyright holders?
• Implications for products based on Sipdroid
• Getting additional features into Sipdroid

Can I develop closed source products with Sipdroid?

Often we get inquiries for an alternate licensing of Sipdroid, from companies interested in using Sipdroid in their products. The goals are building a commercial application, writing their own user interface instead of the one that comes in default with the project and use Sipdroid as libraries only.

This is often referred as obtaining full rights on the code thus avoiding the strict terms of the GPL license.

The answer is no. All details are given below.

Who are the copyright holders?

In order to achieve such an alternate licensing, a company would have to make commercial arrangements with all copyright holders of Sipdroid which are:

• The Sipdroid Open Source Project (http://sipdroid.org)
• Hughes Systique Corporation, USA (http://hsc.com)
• Luca Veltri - University of Parma - Italy (http://mjsip.org)

These organisations are made up of individual authors contributing to the software that would all have to be dealt with. Every author finding lines of his code in a product would be in position to accuse the violator for infringing his copyrighted work.

So it is quite impossible to obtain a commercial license. Sipdroid is committed to open source. Being such it benefits every day, and it is driven by the community.

Implications for products based on Sipdroid

The most important parts of the GPL that should be first understood by every user of the code are:

• The copyright messages attributing to the authors have to be kept intact.
• A download link for the modified source code has to be offered.

Don't mix up GPL terms with L-GPL, the lesser GPL which can be used for libraries. The code of MJSIP (which looks like a library) and Sipdroid were not released under the L-GPL. Sipdroid is not a library.

It is a program which implies that all code added, such as user interfaces and other proprietary stuff, needs to be published under the GPL (see section 5 for details). How the complete source code has to be offered is written in section 6. The license itself also needs to be offered when downloading - not after installation.

Getting additional features into Sipdroid

Every company or individual is invited to add more features to the Sipdroid project. The project has an open policy on adding new members accepting code changes (as long as the code changes don't introduce new bugs).

You can also enter requests for enhancements into the Issue Tracker, and they will eventually be implemented by somebody else.