ProChess Open Source

ProChess includes separately licensed open-source software. ProChess itself is proprietary software; the licenses listed below apply to the identified third-party components.

ProChess 1.4.2

Released October 2026 for Apple silicon Macs.

The complete corresponding-source archive includes source revisions, ProChess modifications, licenses, attribution, build instructions, toolchain details, and the neural-network files distributed with this version.

Download ProChess 1.4.2 corresponding source (tar.gz, approximately 142 MiB)

SHA-256:

c549035df0f8e57b36dde2a4913e54b50e77daaea93f0c5987e9b721ad77835a  ProChess-1.4.2-open-source.tar.gz

The source archive is also available from the ProChess open-source releases repository. GitHub’s automatically generated “Source code” downloads are snapshots of that release repository; use the attached ProChess-1.4.2-open-source.tar.gz asset for the complete corresponding-source bundle.

Included components

• Stockfish 19 — GNU General Public License version 3 or later
• Leela Chess Zero 0.32.1 and lczero-common — GNU General Public License version 3 or later
• Abseil 20240722.0 — Apache License 2.0
• Maia v1.0 neural-network models — GNU General Public License version 3
• Stockfish NNUE networks — Creative Commons CC0 1.0 Universal

Refer to the archive for complete license texts, notices, exact revisions, checksums, and modification details.

Questions

For questions about ProChess’s use of open-source software, please use the customer support form.