This blog is updated daily.
A general description is here.
The list of compilers searched for ‘F95’ has been modernized, and that chosen for ‘FC’ will be used as the default. in particular, ‘gfortran’ is now the first choice, not ‘f95’. Set ‘FC’ in ‘config.site’ to override this if necessary.
The interpretation of source code with extension ‘.f’ is changing. Previously this denoted FORTRAN 77 code, but current compilers no longer have a FORTRAN 77 mode and interpret it as ‘fixed-form’ Fortran 90 (or later where supported) code. Extensions ‘.f90’ and ‘.f95’ continue to indicate ‘free-form’ Fortran code.
Legal FORTRAN 77 code is also legal fixed-form Fortran 95; however this change legitimizes the use of later features, in particular to replace features marked ‘obsolescent’ in Fortran 95 which compilers have started to warn about.
New macros ‘CXX_VISIBILITY’ and ‘FC_VISIBILITY’ analogous to ‘C_VISIBILITY’ and ‘F77_VISIBILITY’.
‘tools::Rd2latex()’ now uses UTF-8 as its default output encoding.
The ‘f77_f2c’ script has been removed: it no longer sufficed to compile the ‘.f’ files in R.