Completely Removing R on Ubuntu

[EWeiss]

When I do a routine apt update and apt upgrade running ubuntu, I get two error messages:

An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/ InRelease: The following signatures were invalid: EXPKEYSIG 51716619E084DAB9 Michael Rutter marutter@gmail.com
W: Failed to fetch https://cloud.r-project.org/bin/linux/ubuntu/bionic-cran35/InRelease The following signatures were invalid: EXPKEYSIG 51716619E084DAB9 Michael Rutter marutter@gmail.com

Any suggestions on how to eliminate the message? "InRelease" is a PGP signature. I have removed large parts of R and I'm willing to delete R and re-install it.

[andresrcs]

Just update the key.

From CRAN documentation:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9 

[padames]

Thanks, why did I have to do this? Do these keys have an expiration date?

[EconomiCurtis]

There's a discussion of what lead to this update on the UBUNTU PACKAGES FOR R page on cran https://cran.r-project.org/bin/linux/ubuntu/README.htm.

NOTE: There was an issue with a second key found on the Ubuntu keyserver. Details and how to remove can be found at http://rubuntu.netlify.com/post/changes-to-cran-ubuntu-webpage-regarding-apt-secure-key/.