Changes to the standard don't instantly, or even eventually, cause corresponding changes in implementations. Code that needs to be portable to many implementations will need to worry about line length limits for a long time into the future.
The Venn diagram of Fortran feature availability in the various actively maintained Fortran compilers is very messy, and the ISO standard is definitely not a subset of any of them. Standard-conforming code is not necessarily portable, and highly portable code is not necessarily standard-conforming, especially since Fortran '95.
The Venn diagram of Fortran feature availability in the various actively maintained Fortran compilers is very messy, and the ISO standard is definitely not a subset of any of them. Standard-conforming code is not necessarily portable, and highly portable code is not necessarily standard-conforming, especially since Fortran '95.