brms 2.14.11

New Features

• Turn off normalization in the Stan model via argument normalize.
  to increase sampling efficiency thanks to Andrew Johnson. (#1017, #1053)
• Enable posterior_predict for truncated continuous models
  even if the required CDF or quantile functions are unavailable.
• Update and export validate_prior to validate priors supplied by the user.
• Add support for within-chain threading with rstan (Stan >= 2.25) backend.
• Apply the R2-D2 shrinkage prior to population-level coefficients
  via function R2D2 to be used in set_prior.
• Extend support for arma correlation structures in non-normal families.
• Extend scope of variables passed via data2 for use in the
  evaluation of most model terms.

Other Changes

• Improve numerical stability of ordinal sequential models
  (families sratio and cratio) thanks to Andrew Johnson. (#1087)

Bug Fixes

• Allow fitting multinomial models with the
  cmdstanr backend thanks to Andrew Johnson. (#1033)
• Allow user-defined Stan functions in threaded models. (#1034)
• Allow usage of the : operator in autocorrelation terms.
• Fix Stan code generation when specifying coefficient-level
  priors on spline terms.
• Fix numerical issues occurring in edge cases during
  post-processing of Gaussian processes thanks to Marta Kołczyńska.
• Fix an error during post-processing of new levels in
  multi-membership terms thanks to Guilherme Mohor.
• Fix a bug in the Stan code of threaded wiener drift diffusion
  models thanks to the GitHub user yanivabir. (#1085)
• Fix a bug in the threaded Stan code for GPs with categorical
  by variables thanks to Reece Willoughby. (#1081)
• Fix a bug in the threaded Stan code when using QR decomposition
  thanks to Steve Bronder. (#1086)