1.Enter R-project
2.click“CRAN mirror”
3.choose one like “TUNA Team, Tsinghua University”
4.click”Download R for Windows”
5.click”base”
6.click”Download R x.x.x for Windows”,the biggest font is the lastest version at present.
7.install
Named the floder with the version number，then default&next
8.RStudio->Tools->Global Options->R version->Choose a specific version of R->Browse->choose the version just downloaded->OK->restart
9.View version>R.Version()$version.string
Reference
R | 如何更新R版本及Rstudio–佩小奇奇蒂蒂花栗鼠
–CSDN