Cannot install package lme4 (problem with RcppEigen?)

[Toscanella]

I'm really not good with R and hope to get some easy and clear answers thank you <3

17 warnings and 2 errors generated.
make: *** [fastLm.o] Error 1
ERROR: compilation failed for package ‘RcppEigen’

• removing ‘/Library/Frameworks/R.framework/Versions/3.6/Resources/library/RcppEigen’
  Warning in install.packages :
  installation of package ‘RcppEigen’ had non-zero exit status
  ERROR: dependencies ‘Matrix’, ‘minqa’, ‘nloptr’, ‘RcppEigen’ are not available for package ‘lme4’
• removing ‘/Library/Frameworks/R.framework/Versions/3.6/Resources/library/lme4’
  Warning in install.packages :
  installation of package ‘lme4’ had non-zero exit status

The downloaded source packages are in
‘/private/var/folders/2v/d0kf09sx4y95wkfytrxlt6g40000gn/T/RtmplV9iyg/downloaded_packages’

And when I tried to install RcppEigen, came a warning "unable to access index for repository https://cran.rstudio.com/bin/macosx/el-capitan/contrib/3.6:
cannot open URL 'https://cran.rstudio.com/bin/macosx/el-capitan/contrib/3.6/PACKAGES'

..and package which is only available in source form, and may need compilation of C/C++/Fortran: 'RcppEigen'

..and ‘RcppEigen’ had non-zero exit status

(as a new user cannot copy than 1 link. I hope this is enough clear..

[FJCC]

It looks like you have a very old version of R. If you run

sessionInfo()

the version of R will be the first item in the output. Here is the beginning of what I get

 sessionInfo()
R version 4.3.1 (2023-06-16 ucrt)

If you are using version 3.6, you should update R.

[Toscanella]

Thank you for this so much! I thought I would have checked R for updates but clearly I didn't.

"This version of R is 3.6.1
There is a newer version of R on CRAN which is 4.3.2

Do you want to visit CRAN now?"

What do I need to do? Typing YES and pressing ENTER doesn't happen anything

[FJCC]

You can go to the web site https://www.r-project.org/. Near the top, there is a Getting Started section where you can choose a CRAN mirror (a location to download from) and then download and install R. If you need more explicit instructions, tell us what operating system you have.

[Toscanella]

I downloaded the newest version 4.3.2 and got the packages I wanted smoothly. Thank you so much for your help!