Update existing packages to new version of R

update_packages_to_new_r_version.r

library(gtools)

installed <- c()

update <- function(p) {
  pd <- packageDescription(p, fields=c('Built'))
  pd <- gsub(";.*", "", pd)
  if (!is.na(pd) && pd != 'R 4.0.4') {  # mention the target versions here
    for (d in getDependencies(p)) {
      update(d)
    }
    if (!is.element(p, installed)) {
      install.packages(p)
    }
    installed <<- c(installed, p)
    print(paste("Installed", length(installed), "packages"))
  }
}

packages <- rownames(installed.packages())
print(paste("Installing", length(packages), "packages"))
for (p in packages) { 
  update(p) 
}