Multi-licensing

Through multiple licensing, users have multiple software licenses to choose from. So a program can be used, for example under an open source license such as the GPL and under a proprietary license. Such license selection is then also called dual licensing system or model. It is also possible to use several open source licenses such as the GPL and a BSD license, to which to choose.

Prominent examples of double licensing in the software field are Qt, MySQL, Asterisk, Sendmail and Perl ( GPL and Artistic License ).

Benefits

This licensing principle, companies can develop their own applications without having to own this again making it open - source license. So it is possible on one hand to promote the open source model for the development and distribution of software, and on the other to establish a professional business model, where software licenses can be sold without restrictions. For a multi-licensing to further address the possibility to provide the software with proprietary extensions.

Buyer of a multi- licensed software are also not tied to the sometimes very restrictive specifications for the transfer of software under a free license. The development of free software is encouraged, without having to rely on donations.

Disadvantages

For a multiple licensing talks that are licensing companies could exploit the work of open source developers. In addition, the developing company could it reserved the right to stop at some point the development of the open version.

However, as mentioned controversial and rare is the fact that for some open source licenses, the control over the development of the software can easily go to the community or to financially superior enterprise. A developmental arrest of a licensed under the GPL software is far says that the software is no longer developed. The GPL grants each user the right to modify the Software in any, including further.

Considerable dispute, whether the initiator of an open source project, which brings its software under a dual license to market, the further development of the community can incorporate into their product to market them as the GPL under another license.

Small businesses generally run the risk of " losing " their open source software projects to large companies.

• Software License