Changes in version 2.3.1 (2025-07-01)                  

This is a minor release that changes the following...

step1_down() and step1_sample_mvt()

  - Replaced sigma with chisq for multi-temperature models
  - The residual error standard deviation (sigma) is now sampled from
    its own distribution rather than being treated as fixed.

step1_sample_mvt()

  - Updated to align with step1_down()
  - Added ... (ellipsis) to support optional arguments passed to
    minpack.lm::nlsLM() during model fitting.

excursion()

  - Updated procedure for excursion() to draw from multi-t dist like
    used in step1_down() and step1_sample_mvt().

                 Changes in version 2.2.1 (2025-05-27)                  

  - Fixed a minor plot issue in the vignette.

                 Changes in version 2.2.0 (2025-05-19)                  

This is a minor release which adds extra functionality to existing
functions plus a vignette has been added that gives more background to
the package.

Enhancements

step1_plot_diagnostic()

  - Includes validation data in observed vs predicted and residuals vs
    predicted scatter plots, if provided.
  - Adds a new plot: residuals vs time, color-coded by temperature, and
    includes validation data points when present.
  - Vignette updated to reflect that the function now generates five
    plots (previously four).

Plotting Functions (step1_plot_CI(), step1_plot_desc(), step1_plot_PI(), step1_plot_pred(), step1_plot_T())

  - xlim and ylim now truncate the visible plot area only, without
    removing data used in the plot.

Bug Fixes

step1_plot_diagnostic()

  - Fixed QQ plot to show quantiles for all data, rather than
    temperature-specific quantiles.

step1_down() and step1_down_basic()

  - Added ... to allow passing optional arguments to minpack.lm.
  - When reparam = TRUE, now prints a message: default lower bounds
    are 0, but custom bounds may be specified.
  - Fixed issue with Kelvin temperature inputs.

Documentation

  - Updated function descriptions across all relevant functions for
    clarity and completeness.

                 Changes in version 2.1.1 (2025-01-20)                  

This is a minor release updating authors and email addresses

                 Changes in version 2.1.0 (2025-01-08)                  

This is a major release adding new functionality, adjusting the data
sets and documentation.

New features

  - step1_down_basic() This new function allows for rapid testing of the
    fit without all of the features.

  - antigenicity Changed example data and added a validation column.

  - step1_down() Adjusted the help page and added validation options to
    the examples. The function will now also return sampled parameters,
    reducing the need for the step1_sample_mvt function.

  - step1_plot_diagnostic() Added argument to use either classic,
    standardized or studentized residuals.

                 Changes in version 2.0.2 (2024-10-21)                  

This release has a minor bug fix and additional descriptions added.

Bug fixes

  - step1_sample_mvt() Fixed issue when no values at time point zero

  - potency.rda File data adjusted slightly

  - step1_down() Added to some arguments' description and new print when
    any of the k3 draws are below zero.

                 Changes in version 2.0.0 (2024-02-13)                  

This is a major release adding a few new functions and fixing a bug.

New features

  - step1_down_rmse() added which allows the user to calculate the root
    mean squared error for their data and chosen parameters

  - step1_down_diagnostic() added which allows the user to plot residual
    diagnostic plots after fitting the model

  - step1_sample_mvt() added which allows the user to draw a chosen
    number of sample parameters from the multivariate t distribution for
    their own analyses

  - step1_down() now accepts an extra argument validation which
    sidelines some of the data allowing the user to save it for testing
    purposes

  - step1_plot_desc() now accepts an extra argument validation which
    sidelines some of the data allowing the user to save it for testing
    purposes

Bug fixes

  - When selecting a temperature outside the data set for step1_plot_T()
    the colours of the prediction line and the ribbon are now consistent
  - When using the argument temp_pred_C within step1_down() no longer
    are predictions duplicated if the temperature is already in the data
  - Issue when no time = 0 rows present in the data and no parms
    provided to step1_down() now resolved

                 Changes in version 1.0.0 (2023-12-10)                  

  - Added a NEWS.md file to track changes to the package.