This blog is updated daily.
A general description is here.
Support for the converters for use with ‘.C()’ has been removed, including the oft misused non-API header ‘R_ext/RConverters.h’.
The 'reference manual' on the Windows GUI menu and included in the installer is now the full reference index, including all base and recommended packages.
Package ‘parallel’ has been added to the reference index (‘refman.pdf’.
The full reference index (‘fullrefman.pdf’) was missing packages ‘compiler’, ‘parallel’ and ‘splines’.