Changes in version 1.9 (2024-07-05)                   

    o   subplex now requires R version 4.1 or later.

    o   The only changes are invisible to the user, allowing subplex to
	stay up to date with development of R.

                  Changes in version 1.8 (2022-04-12)                   

    o   The only changes are invisible to the user, allowing subplex to
	stay up to date with development of R.

                  Changes in version 1.7 (2022-01-16)                   

    o   The only changes are invisible to the user, allowing subplex to
	stay up to date with development of R.

                  Changes in version 1.6 (2020-02-23)                   

    o   The FORTRAN source code has been streamlined.  Many special
	cases which are not used in the R package have been removed.