Platforms

• This will be the last release to support Python3.8.
• Add Python 3.13 support.
• Add muslinux wheel package.
• This will be the last release to support Java 1.8

Builds

• dependencies (protobuf, abseil, re2, highs) are now seperated shared libraries
• Windows libraries are now dll

Dependencies

C++

• Protobuf 29.3
• CoinUtils: 2.11.12
• Osi: 0.108.11
• Clp: 1.17.10
• Cgl: 0.60.9
• Cbc: 2.10.12
• HiGHS: 1.9.0
• Scip: v920
• benchmark: 1.9.1

Graph

• Old graph classes (EbertGraph, StarGraph, ForwardEbertGraph, ForwardStarGraph) have been removed. Use ReverseArcListGraph<> and ListGraph<> instead. Those are conceptually similar, but typically perform better. APIs are mostly compatible.

CP-SAT

• Improve the no_overlap_2d layer (propagation, presolve, cuts)
• Add RandomHalfBranching search heuristics
• Improve Cumulative propagation and cuts
• Rewrote the hint transformation during presolve. Feasible and complete hints should now be preserved after presolve
• Rewrite and optimize the linear expression part of the python layer
• Improve shared tree workers, implement job affinity with workers
• Add scheduling samples
• Support 1-var affine expressions in the Automaton constraint
• Support 1-var affine expressions in the Element constraint
• Speed up LNS
• Tens of fixes for bugs found by fuzzer

Linear Solver

• Add WriteModelToMpsFile to MPSolver in Java, Python and .NET

Math Opt

• Add Xpress support.

Model Builder

• Speedup of the python expression part.
• Add HiGHS support.

SCIP

• This is likely the last release of SCIP build with glop
• We will transition to SCIP with SOPLEX builds
• This is already the case for the Bazel build

Known Issues

• MathOpt: python_math_opt_solver_test failed on macOS [#4460]
• cmake: MacOS Intel based python wheel do not contains mypy files [#4540]
• cmake: cxx_graph_shortest_paths_test (Timeout) [#4539]

Full Changelog: https://github.com/google/or-tools/compare/v9.11...v9.12