Problems getting Stan to run after upgrading to R 4.0.2

Interfaces RStan
6

Thanks
I get this with that request

 Sys.getenv("PATH")
[1] "C:\\RBuildTools\\4.0\\usr\\bin;C:\\Program Files\\R\\R-4.0.2\\bin\\x64;C:\\Program Files (x86)\\Common Files\\Oracle\\Java\\javapath_target_289689671;C:\\Perl64\\site\\bin;C:\\Perl64\\bin;c:\\Rtools\\bin;c:\\Rtools\\mingw_32\\bin;C:\\Windows\\System32;C:\\Windows;C:\\Windows\\System32\\wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0;C:\\Windows\\System32\\OpenSSH;C:\\Program Files\\Intel\\WiFi\\bin;C:\\Program Files\\Common Files\\Intel\\WirelessCommon;C:\\Program Files (x86)\\Intel\\Intel(R) Management Engine Components\\DAL;C:\\Program Files\\Intel\\Intel(R) Management Engine Components\\DAL;C:\\Users\\dalto\\AppData\\Local\\Microsoft\\WindowsApps"
> Sys.getenv("BINPREF")
[1] "C:/Rtools/mingw_$(WIN)/bin/"
> readLines("~/.R/Makevars.win")
Error in file(con, "r") : cannot open the connection
In addition: Warning message:
In file(con, "r") :
  cannot open file 'C:/Users/dalto/Documents/.R/Makevars.win': No such file or directory
> readLines("~/.Renviron")
[1] "PATH=\"${RTOOLS40_HOME}\\usr\\bin;${PATH}\""

Something to do with RTools and RBuildTools?
Regards
Chris