The Stockfish project announced that it had reached an agreement in a lawsuit with ChessBase, which was accused of violating the GPLv3 license by including code from the Stockfish free chess engine in its proprietary products Fat Fritz 2 and Houdini 6 without opening the source code of the derivative work and without informing customers about using GPL code. The agreement provides for the revocation of ChessBase's GPL license to the Stockfish code and for allowing ChessBase to distribute its software.
As part of the agreement reached, ChessBase will stop selling chess programs that use the Stockfish engine, and will notify customers of this by publishing information on its website. Existing customers will be able to continue using programs they have already purchased and will also be able to download copies they have already purchased if ChessBase brings the download process into line with GPL requirements. One year after the agreement is signed, the Stockfish developers will revoke the GPL license and allow their code to be used by ChessBase, which has recognized the value and potential of free software and has pledged to abide by its principles.
The GPL provides for the possibility of revoking the license from the infringer and terminating all the rights of the licensee granted to him by this license. In accordance with the license termination rules adopted in GPLv3, if violations were detected for the first time and eliminated within 30 days from the date of notification, the rights to the license are restored, and the license is not completely revoked (the contract remains intact). Rights are returned immediately also in case of elimination of violations, if the copyright holder has not notified the violation within 60 days. If the deadlines have expired, then the violation of the license can be interpreted as a violation of the contract, for which penalties can be obtained from the court.
To prevent possible violations in the future, ChessBase will appoint a separate person who will monitor compliance with the requirements of the GPL. The company will also create a website, foss.chessbase.com, which will publish information about open source products. In addition, ChessBase will open under the GPL or a compatible license implementations of neural networks supplied for use with Stockfish. The agreement does not provide for financial compensation and damages, since the Stockfish project team represents a non-profit community that has sought to comply with the GPL and its rights.
Source: opennet.ru