INSTALLATION:

• R can be installed using C23 (for example with -std=gnu23 or
  -std=gnu2x) with recent compilers including gcc 12-14, Apple
  clang 15-16, LLVM clang 17-20 and Intel icx 2024.2.

  It can be installed with the upcoming (at the time of writing)
  gcc 15, which defaults to C23.

C-LEVEL FACILITIES:

• The functions R_strtod and R_atof now allow hexadecimal constants
  without an exponent, for compatibility with their C99 versions
  (PR#18805).

UTILITIES:

• R CMD build and R CMD check now allow reference output for demo
  scripts (demo/<demo>.Rout.save files) to be shipped with the
  package, as proposed by Torsten Hothorn in PR#18816.

BUG FIXES:

• kappa(A, exact=TRUE) for singular A returns Inf more generally,
  fixing PR#18817 reported by Mikael Jagan.

• Fixed URLs of the sun spots (sunspot.month etc) data sets and
  mention future changes due to recalibration.

• The parser now accepts hexadecimal constants with a decimal point
  without an exponent (taken as p0) as documented in
  ?NumericConstants (PR#18819).

• rbind() now works correctly when inputs include a raw vector and
  a logical, integer or double vector - previously the inclusion of
  the latter was garbled.

• smooth.spline() checks validity of its arguments df.offset and
  penalty: it could segfault if they were NULL.

• isGeneric(<primitive>, fdef=*, getName=TRUE) now also returns the
  name instead of just TRUE, fixing PR#18829 reported by Mikael
  Jagan.

• isGeneric(fdef = print) now works, fixing PR#18369 thanks to
  Mikael Jagan.

• sort(x, method = "qsort") made illegal accesses when x has length
  0.

• dir.create() is protected against being passed an empty string as
  its path argument.

• Silent integer overflow could occur in the 'exact' computations
  for fisher.test() for unrealistic inputs: this is now an error.

• Some invalid C-level memory accesses are avoided for loglin(, margin = NULL).

  loglin(, param = TRUE) no longer gives an error in corner cases
  such as a one-dimensional input.

• dev.capabilities()$events now reports "Idle" if the device
  provides it, fixing PR#18836, thanks to Trevor Davis.

• arima(.., seasonal = <wrong-vector>) correctly errors now, ditto
  for arima0(), thanks to Norbert Kuder's report on the R-devel
  list.

• binomial(<link>)$linkinv(eta) and .. $mu.eta(eta) now also work
  for "logit" link when is.integer(eta).

• as.roman(x) now should work platform independently, also for,
  e.g., x = "IIIII" (= V) and x = "IIIIII" (= VI).

• R CMD Rd2pdf works again on an installed package directory
  containing LaTeX help (from option --latex), thanks to a report
  by Peter Ruckdeschel.