brms 2.16.0

New Features

• Support several methods of the posterior package. (#1204)
• Substantially extend compatibility of brms models
  with emmeans thanks to Mattan S. Ben-Shachar. (#907, #1134)
• Combine missing value (mi) terms with subset addition terms. (#1063)
• Expose function get_dpar for use in the post-processing
  of custom families thank to Martin Modrak. (#1131)
• Support the squareplus link function in all families and
  distributional parameters that also allow for the log link function.
• Add argument incl_thres to posterior_linpred.brmsfit() allowing to
  subtract the threshold-excluding linear predictor from the thresholds in case
  of an ordinal family. (#1137)
• Add a "mock" backend option to facilitate testing
  thanks to Martin Modrak. (#1116)
• Add option file_refit = "always" to always overwrite models
  stored via the file argument. (#1151)
• Initial GPU support via OpenCL thanks to the help
  Rok Češnovar. (#1166)
• Support argument robust in method hypothesis. (#1170)
• Vectorize the Stan code of custom likelihoods via
  argument loop of custom_family. (#1084)
• Experimentally allow category specific effects for
  ordinal cumulative models. (#1060)
• Regenerate Stan code of an existing model via
  argument regenerate of method stancode.
• Support expose_functions for models fitted with the
  cmdstanr backend thanks to Sebastian Weber. (#1176)
• Support log_prob and related functionality in models fitted
  with the cmdstanr backend via function add_rstan_model. (#1184)

Other Changes

• Remove use of cbind to express multivariate models after
  over two years of deprecation (please use mvbind instead).
• Method posterior_linpred(transform = TRUE) is now equal
  to posterior_epred(dpar = "mu") and no longer deprecated.
• Refactor and extend internal post-processing functions
  for ordinal and categorical models thanks to Frank Weber. (#1159)
• Ignore NA values in interval censored boundaries as long as
  they are unused. (#1070)
• Take offsets into account when deriving default priors
  for overall intercept parameters. (#923)
• Soft deprecate measurement error (me) terms in favor
  of the more general and consistent missing value (mi) terms. (#698)

Bug Fixes

• Fix an issue in the post-processing of non-normal ARMA models
  thanks to Thomas Buehrens. (#1149)
• Fix an issue with default baseline hazard knots in cox models
  thanks to Malcolm Gillies. (#1143)
• Fix a bug in non-linear models caused by accidental
  merging of operators in the non-linear formula
  thanks to Fernando Miguez. (#1142)
• Correctly trigger a refit for file_refit = "on_change" if factor level
  names have changed thanks to Martin Modrak. (#1128)
• Validate factors in validate_newdata even when they are simultaneously
  used as predictors and grouping variables thanks to Martin Modrak. (#1141)
• Fix a bug in the Stan code generation of threaded mixture models
  with predicted mixture probabilities thanks to Riccardo Fusaroli. (#1150)
• Remove duplicated Stan code related to the horseshoe prior
  thanks to Max Joseph. (#1167)
• Fix an issue in the post-processing of non-looped non-linear
  parameters thanks to Sebastian Weber.
• Fix an issue in the Stan code of threaded non-looped non-linear
  models thanks to Sebastian Weber. (#1175)
• Fix problems in the post-processing of multivariate meta-analytic
  models that could lead to incorrect handling of known standard errors.