Overview R 3.5.0 was released a few weeks ago. As it changes some (important) internals, packages installed with a previous version of R have to be rebuilt. This was known and expected, and we took several measured steps to get R binaries to everybody without breakage. The question of but how do I upgrade without breaking my system was asked a few times, e.g., on the r-sig-debian list as well as in this StackOverflow question.
After building 10,742 packages on Launchpad, I would like announce that cran2deb4ubuntu3.5 (c2d4u3.5 for short) is now available for testing and maybe even actually use. It wasn’t difficult to find if you know your way around launchpad, but you can find the PPA here: https://launchpad.net/~marutter/+archive/ubuntu/c2d4u3.5 Many things to consider before you add this PPA to your Ubuntu machine. The PPA supplies binaries for Trusty (14.04), Xenial (16.04), and Bionic (18.