The default version of R is now 4.1.
If you need to use the previous version, you can use the command R35 to get that.
If you regularly install packages for yourself, you may need to update your PATH to grab a newer version of the compiler:
PATH=/s/pkg/linux64/gcc/8.3.0/bin:$PATH
You can run that in your shell before you start the R session you’ll be using to install your packages, or you can add it to your ~/.profile to change it permanently in all new shell sessions you start.