This blog is updated daily.
A general description is here.
The ‘grid’ package now allows ‘gpar(fill)’ to be a ‘linearGradient()’, a ‘radialGradient()’, or a ‘pattern()’. The ‘viewport(clip)’ can now also be a grob, which defines a clipping path, and there is a new ‘viewport(mask)’ that can also be a grob, which defines a mask.
These new features are only supported (so far) on Cairo graphics devices and the ‘pdf()’ device.
The graphics engine version, ‘R_GE_version’, has been bumped to 13 and so packages that provide graphics devices should be reinstalled.
‘str(xS4)’ now also shows extraneous attributes of an S4 object ‘xS4’.
There is now support for parallelized Link-Time Optimization (LTO) with
GCC and for ‘thin’ LTO with ‘clong’ _via_ setting the ‘LTO’ macro.
There is support of setting a different LTO flag for the Fortran
compiler, including to empty when mixing ‘clang’ and ‘gfortran’. See
file ‘config.site’.
‘R CMD INSTALL’ and ‘R CMD SHLIB’ have a new flag ‘--use-LTO’ to use LTO when compiling code, for use with R configured with ‘--enable-lto=R’. For R configured with ‘--enable-lto’, they have the new flag ‘--no-use-LTO’.
Packages can opt in or out of LTO compilation _via_ a ‘UseLTO’ field in the ‘DESCRIPTION’ file. (As usual this can be overridden by the command-line flags.)
‘round()’ and ‘signif()’ no longer tolerate wrong argument names, notably in 1-argument calls; reported by Shane Mueller on the R-devel mailing list.
There is now support for parallelized Link-Time Optimization (LTO) with GCC and for ‘thin’ LTO with ‘clang’ _via_ setting the ‘LTO’ macro.
There is support for setting a different LTO flag for the Fortran compiler, including to empty when mixing ‘clang’ and ‘gfortran’ (as on macOS). See file ‘config.site’.
There is a new ‘LTO_LD’ macro to set linker options for LTO compilation, for example to select an alternative linker or to parallelize thin LTO.
On platforms using ‘configure’ option ‘--with-internal-tzcode’, additional values ‘"internal"’ and (on macOS only) ‘"macOS"’ are accepted for the environment variable ‘TZDIR’. (See ‘?TZDIR’.)
On macOS, ‘"macOS"’ is used by default if the system timezone database is a newer version than that in the R installation.