C-LEVEL FACILITIES:

• The definition of DL_FUNC in R_ext/Rdynload.h has been changed to
  be fully C-compliant. This means that functions loaded via for
  example R_GetCCallable need to be cast to an appropriate type if
  they have any arguments.

• .Machine has a new element sizeof.time_t to identify old systems
  with a 32-bit type and hence a limited range of date-times (and
  limited support for dates millions of years from present).

PACKAGE INSTALLATION:

• (Windows) The default C++ standard had accidentally been left at
  C++11 when it was changed to C++14 on Unix.

BUG FIXES:

• As "POSIXlt" objects may be “partially filled” and their list
  components meant to be recycled, length() now is the length of
  the longest component.

• as.POSIXlt.Date() could underflow for dates in the far past (more
  than half a million years BCE).

• as.Date.POSIXlt(x) would return "1970-01-01" instead of NA in R
  4.2.2, e.g., for

      x <- as.POSIXlt(c("2019-01-30","2001-1-1"))
      x$mon <- c(0L, NA); as.Date(x)
  

• R CMD check failed to apply enabled _R_CHECK_SUGGESTS_ONLY_ to
  examples and vignettes (regression in R 4.2.0).

• R CMD check did not re-build vignettes in separate processes by
  default (regression in R 4.2.0).

• Running examples from HTML documentation now restores previous
  knitr settings and options (PR#18420).

• Quartz: fonts are now located using Core Graphics API instead of
  deprecated ATS which is no longer supported in the macOS 13 SDK
  (PR#18426). This also addresses an issue where the currently
  used font in the Quartz device context was not correctly
  retained.

• (Windows) Math symbols in text drawing functions are again
  rendered correctly (PR#18440). This fixes a regression in R
  4.2.1 caused by a fix in PR#18382 which uncovered an issue in
  GraphApp due to which the symbol charset was not used with TT
  Symbol font face.

• (Windows) Installing a package with a src/Makefile.{win,ucrt}
  file includes ~/.R/Makevars.win64 in the search for user
  makevars, as documented in “R Installation and Administration”
  and done for packages with a src/Makevars.{win,ucrt} file.

• format(<POSIXlt_w/_unbalanced_sec>, "....%OS<n>") with n > 0 no
  longer accidentally uses the unbalanced seconds, thanks to
  Suharto Anggono's report (including patch) in PR#18448.

• solve.default(a, b) works around issues with some versions of
  LAPACK when a contains NA or NaN values.

• When UseMethod() cannot dispatch, it no longer segfaults
  producing the error message in case of a long class(), thanks to
  Joris Vankerschaver's report (including patch) in PR#18447.

• When example(foo, ..) produces graphics on an interactive device
  it needs to open itself, it now leaves devAskNewPage() unchanged
  even when it was FALSE, thus fixing a 14 years old ‘’.

• packageDescription() again catches errors from encoding
  conversions. This also fixes broken packageVersion() in C locale
  on systems where iconv does not support transliteration.