This blog is updated daily.
A general description is here.
Performance of ‘substr()’ and ‘substring()’ has been improved.
Detection of flags for C++98/11/14/17 has been improved: in particular if CXX??STD is set, it is tried first with no additional flags.
New macro ‘F_VISIBILITY’ as an alternative to ‘F77_VISIBILITY’. This will become the preferred form in R 3.6.0.
‘writeLines(readLines(fnam), fnam)’ now works as expected, thanks to Peter Meissner's PR#17528.
‘setClassUnion()’ no longer warns, but uses ‘message()’ for now, when encountering “non local” subclasses of class members.