r-base is already the newest version (3.5.2-1bionic)

After a great deal of apparently irrelevant kerfuffle, with which I have 
been boring this list, I managed to do:

     sudo apt-get dist-upgrade

without getting error messages.  I was told that there was nothing to 
do.  I then (to make sure?) did:

     sudo apt-get install r-base

and was told:

r-base is already the newest version (3.5.2-1bionic).
0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.

However when I run R I get version 3.5.1.  I did:

     whereis R

and got:

/usr/bin/R /usr/lib/R /usr/lib64/R /etc/R /usr/local/lib/R /usr/share > /usr/share/man/man1/R.1.gz /usr/share/man/man1/R.1

I have tried all of the executable R files in the listed locations, and 
with each one of them I get version 3.5.1.

So how do I get 3.5.2 to show up?  There must be *something* simple that 
I can do!  (Dirk:  Can you set me on the path?)

cheers,

Rolf Turner

Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276