Changes in version 1.6 (2026-10-23)                   

Bug fix

  - initialization = "stm" (including stmSeed): the sentiment-discourse
    coefficients kappa_s were always initialized to zero, because the
    STM topic coefficients were read where the content-covariate
    interaction coefficients were intended. kappa_t and kappa_s are now
    initialized from the STM's content-covariate effects (intercept and
    slope of a document-weighted least-squares fit on the centered
    levels of initializationVar), which reproduces the STM topic-word
    distributions exactly for a binary initializationVar. On the
    Gadarian example this gives a higher final ELBO and faster
    convergence; fits with initialization = "stm" will differ from
    sts 1.5. An informative error is now given if stmSeed has no content
    covariate matching initializationVar.

Removal of the stm dependency

  - The package no longer depends on the stm package, which is scheduled
    for archival on CRAN. Apart from the bug fix above, results are
    numerically identical to sts 1.5 for the same random seed.
      - The spectral (anchor word) initialization used by initialization
        = "anchor" (the default) and the STM fit used by initialization
        = "stm" are now implemented internally (R/stmPort.R,
        src/stmfuns.cpp), adapted from stm 1.3.8 (MIT license; the stm
        authors are credited in Authors@R and inst/COPYRIGHTS).
      - New exported functions textProcessor(), prepDocuments() and
        make.heldout(), ported from stm, so that raw text can be
        prepared for sts() and held-out data created without stm.
      - New data set gadarian (from stm) used in the examples.
      - A prefit STM model can still be supplied through stmSeed.
  - sts() now gives an informative error for an unknown initialization
    value.
  - Updated the reference to Chen and Mankad (2025), Management
    Science 71(7).
  - The vignette is now registered through the R.rsp::asis engine.
  - Added SnowballC (used for stemming in textProcessor()) to Imports
    and removed stm, knitr and rmarkdown.

                         Changes in version 1.5                         

  - Previous CRAN release.