                  Changes in version 1.15 (2026-08-28)                  

  - option AK (Akash), WSH (weighted Shanker) and WSU (weighted Sujatha)
    were added in frailty.fit function

                  Changes in version 1.14 (2025-08-24)                  

  - corrected issue in frailty.fit function for option GE
  - option JSW (Jorgensen-Seshadri-Whitmore) was added in frailty.fit
    function

                  Changes in version 1.13 (2025-04-05)                  

  - option GE (generalized exponential) was added in frailty.fit
    function

                  Changes in version 1.12 (2024-09-23)                  

  - corrected the frailty variance for the MIG and MBS models

                  Changes in version 1.11 (2024-09-02)                  

  - corrected the observed log-likelihood function for the MIG model
  - option MBS (mixture of Birnbaum-Saunders) was added in frailty.fit
    function

                  Changes in version 1.10 (2024-06-16)                  

  - corrected the variance of frailty for the MIG model and its
    estimated standard error

                  Changes in version 1.9 (2024-03-17)                   

  - option MIG (mixture of inverse gaussian) was added in frailty.fit
    function

                  Changes in version 1.8 (2023-09-26)                   

  - removed dependency of frailtypack package

                  Changes in version 1.7 (2023-08-09)                   

  - option TN (truncated normal) was added in frailty.fit function

                  Changes in version 1.6 (2023-05-15)                   

  - fixed bugs in summary.extrafrail function to compute p-values

                  Changes in version 1.5 (2023-04-06)                   

  - option exp (exponential) was added in frailty.fit function as
    baseline model
  - fixed bugs in summary.extrafrail function for pe distribution as
    baseline model

                  Changes in version 1.4 (2023-03-29)                   

  - option pe (piecewise exponential) was added in frailty.fit function
    as baseline model

                  Changes in version 1.3 (2023-01-29)                   

  - option BS (Birnbaum-Saunders) was added in frailty.fit function

                  Changes in version 1.2 (2022-09-26)                   

  - fixed bugs in summary.extrafrail function

                  Changes in version 1.1 (2022-08-06)                   

  - function frailtyWL was deprecated
  - function frailty.fit was included. Besides the shared weighted
    Lindley frailty model, this function allows to perform estimation
    for the shared gamma and shared inverse gaussian frailty models.
