v2.38.0 (13 January 2026)

• Allow min:max indexing to always succeed if it is an empty selection. (#3362)

• Updated scalar templating in the serializer. (#3355)

• Removed the uses of forward_as from the stan repo and adds if constexpr where possible. (#3357)

• Updated Pathfinder writer to avoid indexing past vector length. (#3364)

Documentation

HTML

• Stan User's Guide 2.38
• Stan Language Reference Manual 2.38
• Stan Language Functions Reference 2.38

PDF

• Stan User's Guide 2.38 pdf
• Stan Language Reference Manual 2.38 pdf
• Stan Language Functions Reference 2.38 pdf

v2.38.0-rc1 (6 January 2026)

release/v2.38.0: updating version numbers (#3369)

v2.37.0 (2 September 2025)

• Fixed a memory leak in laplace_sample. (#3324)
• Dramatically reduce the memory footprint of Pathfinder when PSIS resampling is disabled. Note that this change involves changes to thread scheduling that may result in the same seed returning draws in a different order when multiple threads are used, but the unordered set of draws should be unchanged. (#3325)
• Fixed a missing size check by directing all std::vector assigns through size-aware version. (#3352)
• Implemented serialization and deserializtion for sum_to_zero matrix. (#3342)
• Fixed stepsize adaption being completely reset when passing 0 for the size of term_buffer. (#3346)

Documentation

HTML

• Stan User's Guide 2.37
• Stan Language Reference Manual 2.37
• Stan Language Functions Reference 2.37

PDF

• Stan User's Guide 2.37 pdf
• Stan Language Reference Manual 2.37 pdf
• Stan Language Functions Reference 2.37 pdf

v2.37.0-rc4 (22 August 2025)

Tagging v2.37.0-rc4

v2.37.0-rc3 (18 August 2025)

Tagging v2.37.0-rc3

v2.37.0-rc2 (12 June 2025)

Tagging v2.37.0-rc2

v2.37.0-rc1 (5 June 2025)

Tagging v2.37.0-rc1

v2.36.0 (10 December 2024)

• Added de/serialization for the stochastic_row_matrix and stochastic_column_matrix types. (#3298, #3304)
• Added de/serialization for the sum_to_zero_vector type. (#3308)
• Relaxed restrictions on HMC to allow running when a model has no parameters. (#3071, #3303)
• Updated rvalue() functions that use multi_index to return an Eigen expression of multi indexing instead of eagerly creating a new matrix from the indices. (#3250)
• Improved error messages when user-specified initializations fail. (#3291)
• Fixed progress output formatting being inconsistent for the non-adaptive samplers. (#3296)
• Improved parsing of Stan CSV files to allow for getting MCMC sample from fixed_param and samples with saved warmup draws and to be able to correctly get ADVI sample. (#3311)
• Improved parsing of Stan CSV files when they contain nan or infinite values. (#3318)
• Added a new stan::mcmc::chainset object, exposing split-Rhat, split-ESS and Monte Carlo standard error diagnostics. This replaces the chains<> object. (#3312, #3313)
• Fixed a header include order issue that caused compilation with -DSTAN_MODEL_FVAR_VAR to fail for certain models. (#3294)
• Removed support for adding makefile variables in ~/.config/stan/make.local. Use the make/local file in the Stan directory instead. (#3295)

Documentation

HTML

• Stan User's Guide 2.36
• Stan Language Reference Manual 2.36
• Stan Language Functions Reference 2.36

PDF

• Stan User's Guide 2.36 pdf
• Stan Language Reference Manual 2.36 pdf
• Stan Language Functions Reference 2.36 pdf

v2.36.0-rc2 (3 December 2024)

Tagging v2.36.0-rc2

v2.36.0-rc1 (25 November 2024)

Merge remote-tracking branch 'origin/develop' into release/v2.36.0