Starting from these versions, the packages will be licensed under LGPLv2.1 instead of the very restrictive GPLv2. This does not change anything to the everyday users of the packages, but is a potential game changer to software developers and those who might want to modify the source code of the packages for commercial purposes. This is because any change of the code under GPLv2 implies that these changes need to be released and made available to everyone, while the LGPLv2.1 allows modifications without releasing the source code. At the same time, both licenses imply that the attribution to the author is necessary, so if someone modifies the code and uses it for their purposes, they still need to say that the original package was developed by this and that author (Ivan Svetunkov in this case). The reason I decided to change the license is that one of software vendors that I sometimes work with pointed out that they cannot touch anything under GPL because of the restrictions above. Moving to the LGPL will now allow them using my packages in their own developments. This applies to such functions as adam(), es(), msarima(), ces(), alm() and others. I don’t mind, as long as they say who developed the original thing.
What happens now? The versions of the
greybox packages under GPLv2 are available on github here and here respectively, so if you are a radical open source adept, you can download those releases, install them and use them instead of the new versions. But from now on, I plan to support the packages under the LGPLv2.1 license.
Finally, a small teaser: colleagues of mine have agreed to help me in translating the R code into Python (actually, I am quite useless in this endeavor, they do everything), so at some point in future, we might see the
greybox packages in Python. And they will also be licensed under LGPLv2.1.