Error msg trying to load R Commander with an older R edition...

Hi folks:

I'm running Linux Mint 19.3 on my machine. Tried to install a more
recent edition of R but I couldn't seem to get it working so I pulled it
off and went with a good, basic install of the edition available through
the software manager. So... I'm running version 3.4.4.

Mucking about with the attempt at a newer edition seems to have left
some excess baggage behind. When I loaded R Commander and attempted to
run it I received the following error message.

Error: package or namespace load failed for ?car? in readRDS(pfile):
  cannot read workspace version 3 written by R 3.6.2; need R 3.5.0 or newer
During startup - Warning message:
package ?Rcmdr? in options("defaultPackages") was not found

I get a similar message in Rkward when I try to load any more packages.

Is there any solution for this? Any "leftovers" I can track down and
delete? Any assistance would be greatly appreciated.

Kind regards...