@rstub . Thank you for the reply.
Could you please provide some more information as to how you've come to that conclusion?
I just had an email exchange with another RStudio Employee who said "That [first paragraph in my previous post] looks sound to me; the default_r_version can be specified in a user's rstudio-prefs.json file, and so it is not necessary to use the (Pro-only) profiles file for that specific, user-level task."
Unless the rstudio-prefs.json file doesn't exist in RStudio Server Open Source, couldn't a user switch from one version of R to another version of R by editing the rstudio-prefs.json file? It certainly appears to be possible from the blog post and the documentation I referred to.
Or, perhaps I'm misunderstanding what you mean by "support" or "multiple versions of R"?
Thank you for engaging, as I think this is an important topic for the community.