This blog is updated daily..
A general description is here.
Bundles of packages are defunct. [In progress: so far R CMD build cannot build them, and R CMD check refuses them.]
stats::clearNames() is defunct: use unname().
Basic regular expressions (extended = FALSE) are defunct in strsplit, grep and friends.
methods::trySilent() is defunct.
Use of ~/.Rconf (which was deprecated in favour of ~/.Rconfig in 2004) has finally been removed.