How do I install rstan with this version issue?

Hi, I am following the instructions on the rstan installation guide hosted on github, and I can install rstan perfectly fine with the newest version of rstudio and version 4.0+ R. But when I try to run a basic model or the install_github pathway I receive this error.

Error in loadNamespace(j ← i[[1L]], c(lib.loc, .libPaths()), versionCheck = vI[[j]]) :
namespace ‘processx’ 3.4.4 is being loaded, but >= 3.5.0 is required

Operating System: Windows OS

Any help is hugely appreciated!

Hi - this is not my forte but one suggestion would be specifically trying to download that package with the latest version - CRAN seems to have version 3.5 available, so you could try install packages → processx, then restart R and try again.