Hans-Dieter Thiel Consulting limited uses a Dual License business model for some its software development libraries and offers licenses for two distinct purposes - commercial and open source development.

Dual Licensing is based on the principle of Quid Pro Quo - "something for something". In return for the advantages you realize from using a Hans-Dieter Thiel Consulting limited product to create your application, we require that you do one of the following:

Contribute to the continued development of the product by purchasing commercial licenses from Hans-Dieter Thiel Consulting limited. This option secures you the right to distribute your application under the license terms of your choice.

Contribute to the Open Source community by placing your application under an Open Source license (e.g. GPL v3). This option secures all users the rights to obtain the application's full source code, modify it, and redistribute it.

If you derive a commercial advantage by having a closed source solution, you must purchase an appropriate number of commercial licenses from Hans-Dieter Thiel Consulting limited. By purchasing commercial licenses, you are no longer obligated to publish your source code.
If you wish to use the open source license of a Hans-Dieter Thiel Consulting limited product, you must contribute all your source code to the open source community and you must give them the right to share it with everyone too.