From today, Transdroid will be distributed under a new license: the GNU General Public License. This is important because it have different permissions than the old license that was used. I want to briefly explain this choice.
I am a strong supporter of free and open-source software. Although not always possible, I believe software should be free to use, adapt, redistribute or even sell. However, I also believe that software released under such conditions should always be free. In particular, I believe we should encourage any derivative works to be free and open-source as well. Until now Transdroid was released with an Apache License 2.0, which is pretty much fully permissive. The change to the GPLv3, which is a copyleft license, ensures any work based on Transdroid version released in the future needs to be released under GPLv3 as well.
Any Transdroid version based on source code, documentation, meta files, etc. of revision 138 or earlier (released Transdroid version 0.13.5 and earlier and beta versions 0.14.0 beta 3 and earlier) are still under the Apache License 2.0, while from revision 139 and onwards (including any future Transdroid releases) will be licensed with GNU General Public License version 3. Transdroid reuses some code released by their own licenses (Apache and LGPL), which will be left in tact.
Hopefully this explains why all future works of (or based on) Transdroid will be open-source forever.