I have used SGMLReader for other projects in the past. I just went out to look at the updates today and noticed the license change from MS-PL/Microsoft EULA to GPL v3. My questions are why was this done, and is this even allowable?
It would appear that the new license is in violation of section 3.D of the MS-PL, which according to the Microsoft Code Gallery, the original code is licensed under:
If you distribute any portion of the software in source code form, you may do so only under this license by including a complete copy of this license with your distribution. If you distribute any portion of the software in compiled or object code form, you may only do so under a license that complies with this license.Going off of the earlier license, it would appear that the move to GPL would also be blocked by the original Microsoft EULA since SGMLReader was released as a Microsoft sample.
Since MindTouch's version of SGMLReader is a derived work that includes the source code from the original library, it would appear that SGMLReader can only be licensed under the MS-PL license (or under the terms of the original Microsoft EULA, depending on which version MindTouch started with) and all contributed source code would have to be released under a compatible license, which GPL v3 is not.
Can you please clarify the status of this project and whether or not permission was granted from the original author to change the license? If this library is now legally under the GPL license, is Mindtouch going to offer a commercial license for the use of the library and how can that license be obtained?
Also, as of which version is SgmlReader under GPL according to Mindtouch? It appears that this change was made as of June 12, 2011, according to the GitHub history. Does this mean that all code prior to June 12, 2011, is still under MS-PL and can continue to be used without the restrictions imposed under the GPL v3 license? I'm guessing that the 1.8.7 version is still under the original non-GPL license and the change to GPL is as of 1.8.8? Is this correct?
My intent is not to be difficult and I respect the work that MindTouch has done to improve and continue this project. However, the change of license is quite concerning to me as a user of the library.