RTools: Toolchains for building R and R packages from source on Windows

Choose your version of Rtools:

RTools 4.3	for R versions from 4.3.0 (R-release and R-devel)
RTools 4.2	for R versions 4.2.x (R-oldrelease)
RTools 4.0	for R from version 4.0.0 to 4.1.3
old versions of RTools	for R versions prior to 4.0.0