[R-pkg-devel] .Fortran opinion

Recently, users of my package rdwd have provided Fortran code for a nice extension of the package.
According to the following site, calling .Fortran() is no longer recommended:
https://github.com/wrathematics/Romp/blob/master/README.md#fortran

Since this is my first time using native code, I'd highly appreciate any thoughts on the following question:
How much additional work should I put into avoiding .Fortran() for long-term CRAN suitability?

Thanks ahead,
Berry

PS: In case you want a look at the (two very short) Fortran routines:
https://github.com/brry/rdwd/tree/master/src
and their call in R:
https://github.com/brry/rdwd/blob/master/R/readRadarFile.R#L119