Basic step to install old versions of R for RStudio Server Pro

install-R-source

# examples for R-4.0.2
sudo wget https://cran.r-project.org/src/base/R-4/R-4.0.2.tar.gz
sudo tar -xvzf R-4.0.2.tar.gz
cd R-4.0.2

# install in /opt/R to make it automatically discovered by RSSP
sudo ./configure --prefix=/opt/R/$(cat VERSION) --enable-memory-profiling --enable-R-shlib --with-blas --with-lapack
sudo make
sudo make install

# use /etc/rstudio/notification.conf to warn for the restart
# be sure no user is active
# check no active session
sudo rstudio-server restart

# update default version of R for the users
# in etc/rstudio/rserver.conf
rsession-which-r=/opt/R/4.0.2