This release adds several algorithms and games, and several process changes.

Support, APIs, and Process changes

• Removed support for Python 3.6
• Added support for Python 3.10
• Upgrade support for newer versions of dependencies
• Rust API: add support for loading bots
• CI tests: added MacOS-11, MacOS-12, and Ubuntu 22.04. Removed CI tests for Ubuntu 18.04.

Games

• Colored Trails
• Dynamic Routing Game: added Sioux Falls network
• Mancala (Kalah)
• Multi-issue Bargaining
• Repeated game transform: add info state strings & tensors, utility sum, finite recall
• Sheriff: add info state tensor

Algorithms

• Boltzmann DQN
• Boltzmann Q-learning
• Correlated Q-learning (Greenwald & Hall)
• Deep average network for FP (mean-field games)
• Nash averaging (Balduzzi et al.)
• Nash Q-learning (Hu & Wellman)

Improvements and other additions

• Example: support mean-field games
• File wrapper: expose to Python and add WriteContents
• Nash bargaining score example

Fixes

• VR-MCCFR with nonzero baselines
• PyTorch policy gradient clipping
• Promote pawn to queen in RBC
• PyTorch and LibTorch DQN: fix for illegal moves

Many other fixes to docs and code quality.

Acknowledgments

Thanks to DeepMind for continued support of development and maintenance of OpenSpiel.

Thanks to all of our contributors:

• Core Team: https://github.com/deepmind/open_spiel/blob/master/docs/authors.md
• All Contributors: https://github.com/deepmind/open_spiel/graphs/contributors