This blog is updated daily.
A general description is here.
win.version() and Sys.info() know about recent and upcoming Windows versions, including if they are running on a 64-bit platform.
The listbox used by select.list() now responds to double-clicking an item (as if the item had been selected and then the OK button pressed).
The header iconv.h is now installed, and can be used by packages in conjunction with PKG_LIBS=-liconv .
The value of "default" for the postscript() 'paper' argument for savePlot() and the windows() graphics device menus is now interpreted as "special" (rather than "a4" or "letter"): it can still be overridden by setting ps.options(). (This changes the default output to be most suitable for inclusion in other documents rather than to produce a page for printing.)
The shortcuts created by the installer now start R in the user's personal folder (typically 'My Documents' or 'Documents').
If Rterm is invoked as 'R', the status code (as passed to q()) is now returned (rather than 0 or 1).
capture.output() completes an incomplete final line of output when file = NULL. (PR#10534)
capture.output() now returns invisibly if output is written to a file/connection.
format.AsIs() did not remove the "AsIs" class and so could go into an infinite loop.
summary.mlm() lost the names of the coefficients when there was only one.
Rdconv was not marking examples files with an encoding if this was known from the package's DESCRIPTION file.
readChar() from a raw vector was reading a number of bytes, not characters.
slotNames() was erroneously treating classes that extend "character" as strings.
R no longer ignores SIGPIPE signals even in processes launched by system(). Instead PR#1959 is handled by a simple error handler which will give an error message in circumstances where none was given before.
The AIC() S4 generic in package stats4 no longer disables dispatch of S3 methods for AIC().
The conflicts check in library() excluded all S4 generics, even where they were unrelated to the function masked. It is now more selective (although still too generous to S4 generics).
\code{\var{<name>}} was not rendered correctly to latex in Rd files for non-alphabetic arguments <name>.
The default method for range() was omitting 'na.rm' for non-numeric objects such as those of class "Date". (PR#10508)
The automatic detection of the domain for message translation was not working correctly for messages in message(), warning() and stop() in packages others than 'base'.
plot.formula() was not passing on '...' on when used with a one-sided formula.
plot.formula() was not accepting expressions for annotations passed to title(). (PR#10525)