• ‘Ops’ group (Arith, Compare,..) methods for matrix-‘"ts"’ now do return (zero length) matrices even when the two series do not overlap, a very partial fix of PR#18972 which is to be fully addressed later.

• ‘tools/fetch-recommended’ can be used instead of ‘tools/rsync-recommended’ to fetch recommended packages into R sources using ‘curl’ on systems without ‘rsync’ or behind firewalls.

CHANGES IN R 4.5.3 PACKAGE INSTALLATION

• C++ standard specifications (‘CXX_STD =’ in ‘src/Makevars*’ and in the ‘SystemRequirements’ field of the ‘DESCRIPTION’ file) are now checked more thoroughly. Invalid values are still ignored but now give a warning, as do contradictory specifications.

• (Preliminary) support for C++26 has been extended to Windows.

• A non-zero exit status from ‘cleanup’, ‘cleanup.win’ or ‘cleanup.ucrt’, if requested via options ‘--clean’ or ‘--preclean’, is now reported with a warning.

CHANGES IN R 4.5.3 BUG FIXES

• ‘all.equal(obj, simple, check.class=FALSE)’ now is true, also when ‘simple’ is a bare atomic vector and ‘obj’ has a simple class, fixing the first part of PR#18971 thanks to Jan Gorecki.

• ‘str(x, give.attr=FALSE)’ no longer shows attributes when ‘x’ is a zero length ‘"Date"’ or ‘"POSIXt"’ object.

• Tweaks to binning for ‘bw.SJ()’ and ‘bw.ucv()’ in the very rare case of data which have an extremely small range compared to their absolute values, e.g., ‘x <- 6e9 + 6:9’.

• Formatting book-type ‘bibentry’ objects now converts LaTeX accents also in the publisher and series fields.

• ‘model.frame(~1, list(), na.action=na.pass)’ and similar “border-line” uses no longer produce invalid data frames, fixing PR#18977, reported with patch by Mikael Jagan.

• ‘length(<POSIXlt>) <- v’ is more careful about balancing, notably when ‘v’ is not integer, thanks to Suharto Anggono's remarks on the mailing list R-devel.

• ‘approx(<x_with_ties>, <y_with_NA>, na.rm = FALSE)’ now should always call the ‘ties()’ function, fixing PR#17604 reported by Bill Dunlap.

• ‘besselJ(1, 1e-15)’ and similar now give correct results, thanks to Leo Mada and other “R-help”ers.

• ‘vignette(<pkg>::<topic>)’ is now a documented usage variant and confines vignette retrieval to the specified package.

• ‘pretty(ch)’ again correctly works with ‘ch’ a character vector of numbers.

• ‘persp()’ labels the three axes correctly also when C level ‘atan2pi()’ is available, fixing PR#19007 by Klaus Schliep.

• Large (tall) subscripts in plotmath expressions are now positioned correctly. They were being positioned too high.

• Large (tall) subscripts in plotmath expressions are now positioned correctly. They were being positioned too high.

• A non-zero exit status from ‘cleanup’, ‘cleanup.win’ or ‘cleanup.ucrt’, if requested via options ‘--clean’ or ‘--preclean’, is now reported with a warning.

CHANGES IN R 4.5.2 patched BUG FIXES

• ‘diff(m, lag, dif)’ for matrix ‘m’ now still returns matrices, also when ‘lag * dif > nrow(m)’ (PR#18972, thanks to Mikael Jagan and Suharto Anggono). ‘diff(<ts-matrix>)’ remains matrix, even when it has length zero.

• ‘model.frame(~1, list(), na.action=na.pass)’ and similar “border-line” uses no longer produce invalid data frames, fixing PR#18977, reported with patch by Mikael Jagan.

• ‘length(<POSIXlt>) <- v’ is more careful about balancing, notably when ‘v’ is not integer, thanks to Suharto Anggono's remarks on the mailing list R-devel.

• ‘approx(<x_with_ties>, <y_with_NA>, na.rm = FALSE)’ now should always call the ‘ties()’ function, fixing PR#17604 reported by Bill Dunlap.

• ‘persp()’ labels the three axes correctly also when C level ‘atan2pi()’ is available, fixing PR#19007 by Klaus Schliep.

• (Preliminary) support for C++26 has been extended to Windows.

• ‘pretty(ch)’ again correctly works with ‘ch’ a character vector of numbers.

• ‘besselJ(1, 1e-15)’ and similar now give correct results, thanks to Leo Mada and other “R-help”ers.

• ‘vignette(<pkg>::<topic>)’ is now a documented usage variant and confines vignette retrieval to the specified package.

• ‘pairwise.t.test()’ misbehaved when subgroups had 0 DF for variance, even with ‘pool.sd = TRUE’. (PR#18594 by Jack Berry.)

CHANGES IN R 4.2.0 BUG FIXES

• ‘identical(attrib.as.set=FALSE)’ now works correctly with data frames with default row names. (Thanks to Charlie Gao's PR#18179.)

• ‘tools/fetch-recommended’ can be used instead of ‘tools/rsync-recommended’ to fetch recommended packages into R sources using ‘curl’ on systems without ‘rsync’ or behind firewalls.

CHANGES IN R 4.5.2 UTILITIES

• ‘tools/fetch-recommended’ can be used instead of ‘tools/rsync-recommended’ to fetch recommended packages into R sources using ‘curl’ on systems without ‘rsync’ or behind firewalls.

• C++ standard specifications (‘CXX_STD =’ in ‘src/Makevars*’ and in the ‘SystemRequirements’ field of the ‘DESCRIPTION’ file) are now checked more thoroughly. Invalid values are still ignored but now give a warning, as do contradictory specifications.

CHANGES IN R 4.5.2 UTILITIES

• ‘tools/fetch-recommended’ can be used instead of ‘tools/rsync-recommended’ to fetch recommended packages into R sources using ‘curl’ on systems without ‘rsync’ or behind firewalls.

• ‘diff(m, lag, dif)’ for matrix ‘m’ now still returns matrices, also when ‘lag * dif > nrow(m)’ (PR#18972, thanks to Mikael Jagan and Suharto Anggono). ‘diff(<ts-matrix>)’ remains matrix, even when it has length zero.

• Tweaks to binning for ‘bw.SJ()’ and ‘bw.ucv()’ in the very rare case of data which have an extremely small range compared to their absolute values, e.g., ‘x <- 6e9 + 6:9’.

• Formatting book-type ‘bibentry’ objects now converts LaTeX accents also in the publisher and series fields.

• Tweaks to binning for ‘bw.SJ()’, ‘bw.bcv()’ and ‘bw.bcv()’ in the very rare case of data which have an extremely small range of very large absolute values.

• ‘all.equal(obj, simple, check.class=FALSE)’ now is true, also when ‘simple’ is a bare atomic vector and ‘obj’ has a simple class, fixing the first part of PR#18971 thanks to Jan Gorecki.

• ‘str(x, give.attr=FALSE)’ no longer shows attributes when ‘x’ is a zero length ‘"Date"’ or ‘"POSIXt"’ object.

• New connection type ‘zstdfile’ for files compressed by ‘zstd’ if R was built with such support. ‘file()’ and ‘gzfile()’ can automagically read such files.

• ‘memCompress()’ and ‘memDecompress()’ have options to use ‘zstd’ compression if R was built with support for it.

• New connection type ‘zstdfile’ for files compressed by ‘zstd’ if R was built with such support. ‘file()’ and ‘gafile()’ can automagically read such files.

• ‘memCompress()’ and ‘memDecompress()’ have optiosn to use ‘zstd’ compression if R was built with support for it.

• When ‘"POSIXlt"’ date-time objects are ‘NA’-padded from subsetting or increasing ‘length’ in the ‘`[`’ or ‘`length<-`’ methods, the ‘"balanced"’ attribute is set to ‘NA’, now; noted in PR#18681, thanks to Mikael Jagan.

• ‘R CMD check’ now handles archives with extension ‘.tar’ or ‘.tar.zstd’ (where ‘zstd’ compression is supported by the R build).

CHANGES IN R 4.5.2 BUG FIXES

• ‘t.test(c(1:3, Inf))’ and similar no longer produce an error but return a (still not so useful) ‘"htest"’ result, fixing PR#18901, thanks to Jesse Alderliesten.

• ‘attr(., "tsp") <- val’ now uses ‘getOption("ts.eps")’ instead of hardwired ‘1e-5’; consequently, ‘ts(.., ts.eps=*)’ now passes ‘ts.eps’ to the ‘"tsp"’ setting C code; both fixing a long-standing ‘FIXME’.

• ‘insertSource()’ now ignores the internal ‘.packageName’ object, avoiding a superfluous message.

• In static HTML help, links to vignette files from the default ‘doc/index.html’ page now also work for packages not installed in the default ‘.Library’, thanks to a report by Patrice Kiener.

• ‘fixInNamespace("<S3method>")’ failed to update the S3 methods table when the generic was not on the search path.

• In plain-text help (‘Rd2txt’), an initial newline from an Rd inline \eqn no longer breaks the paragraph.

• ‘hist(*, log = "x")’ now works without a warning, thanks to Martin Smith's PR#18921.

• Subassigning ‘"POSIXlt"’, i.e., ‘<tdat>[i] <- val’ and ‘<tdat>[[i]] <- val’ now rebalance as they should, thanks to Mikael Jagan's PR#18919.

• ‘<POSIXlt>[*]’ (re-)setting ‘"balanced"’, fixing PR#18681 comment #7, thanks to Mikael Jagan.

• All four of ‘{col,row}{Sums,Means}(Z, na.rm=TRUE)’ now correctly work with complex ‘Z’ where ‘is.na(Re(Z))’ differs from ‘is.na(Im(Z))’, fixing PR#18942, unearthed by Dirk Eddelbuettel.

• Fix for glyph rendering on the ‘quartz()’ device when there is other (“normal”) text drawn on the device. The problem was that the text transformation matrix was not reset so glyphs would be rendered incorrectly (often completely outside the device, i.e., not visible).

• Functions ‘install.packages()’ and ‘download.packages()’ again consult option ‘download.file.method’ when the download method is unspecified.

• Tanguy Barthelemy and colleagues at the ‘R Dev Day’ following Rencontres R in May 2025 extended the help page of ‘lm()’, fixing PR#18058. As suggested by Thomas Soeiro, such notes were also added to the ‘glm()’, ‘poly()’ and ‘splines::bs()’ and ‘ns()’ pages.

• ‘lbeta(1i, 1)’ now signals an error, as ‘lbeta()’ is not implemented for ‘complex’, fixing PR#18946 from Ben Bolker and Kasper Kristensen.

• The Cairo-based SVG device uses ‘pt’ as the default document unit also with Cairo >= 1.17.8 (PR#18912).

• ‘pretty(*, eps.correct = 2)’ has been fixed, e.g., to avoid over 1 million length result for ‘pretty(c(0, 1e-322), eps.correct = 2)’.

• ‘format(dtime, digits=* / format=*)’ is more consistent when the ‘POSIXt’ date-time object ‘dtime’ has fractional (non integer) seconds. Fixes PR#17350, thanks to new contributions by LatinR's ‘R Dev Day’ participants, Heather Turner and Dirk Eddelbuettel; also fixes more cases, notably when ‘format’ contains ‘%OS<nodigit>’.

• ‘lbeta(1i, 1)’ now signals an error, as ‘lbeta()’ is not implemented for ‘complex’, fixing PR#18946 from Ben Bolker and Kasper Kristensen.

• ‘pretty(*, eps.correct = 2)’ has been fixed, e.g., to avoid over 1 million length result for ‘pretty(c(0, 1e-322), eps.correct = 2)’.

• The Cairo-based SVG device uses ‘pt’ as the default document unit also with Cairo >= 1.17.8 (PR#18912).

• The Cairo-based SVG device uses ‘pt’ as the default document unit also with cairo >= 1.17.8 (PR#18912).

• All four of ‘{col,row}{Sums,Means}(Z, na.rm=TRUE)’ now correctly work with complex ‘Z’ where ‘is.na(Re(Z))’ differs from ‘is.na(Im(Z))’, fixing PR#18942, unearthed by Dirk Eddelbuettel.

• Tanguy Barthelemy and colleagues at the ‘R Dev Day’ following Rencontres R in May 2025 extended the help page of ‘lm()’, fixing PR#18058. As suggested by Thomas Soeiro, such notes were also added to the ‘glm()’, ‘poly()’ and ‘splines::bs()’ and ‘ns()’ pages.

• Functions ‘install.packages()’ and ‘download.packages()’ again consult option ‘download.file.method’ when the download method is unspecified.

• Fix for glyph rendering on the ‘quartz()’ device when there is other (“normal”) text drawn on the device. The problem was that the text transformation matrix was not reset so glyphs would be rendered incorrectly (often completely outside the device, i.e., not visible).

• ‘hist(*, log = "x")’ now works without a warning, thanks to Martin Smith's PR#18921.

• Subassigning ‘"POSIXlt"’, i.e., ‘<tdat>[i] <- val’ and ‘<tdat>[[i]] <- val’ now rebalance as they should, thanks to Mikael Jagan's PR#18919.

• ‘<POSIXlt>[*]’ (re-)setting ‘"balanced"’, fixing PR#18681 comment #7, thanks to Mikael Jagan.

• In plain-text help (‘Rd2txt’), an initial newline from an Rd inline \eqn no longer breaks the paragraph.

CHANGES IN R 4.5.0 BUG FIXES

• ‘options(scipen = NULL)’ and other invalid values now signal an error instead of invalidating ops relying on a finite integer value. Values outside the range -9 .. 9999 are now warned about and set to a boundary or to the default ‘0’, e.g., in case of an ‘NA’. This also fixes PR#16322.

• ‘fixInNamespace("<S3method>")’ failed to update the S3 methods table when the generic was not on the search path.

• In static HTML help, links to vignette files from the default ‘doc/index.html’ page now also work for packages not installed in the default ‘.Library’, thanks to a report by Patrice Kiener.

• ‘insertSource()’ now ignores the internal ‘.packageName’ object, avoiding a superfluous message.

• ‘attr(., "tsp") <- val’ now uses ‘getOption("ts.eps")’ instead of hardwired ‘1e-5’; consequently, ‘ts(.., ts.eps=*)’ now passes ‘ts.eps’ to the ‘"tsp"’ setting C code; both fixing a long-standing ‘FIXME’.

• ‘t.test(c(1:3, Inf))’ and similar no longer produce an error but return a (still not so useful) ‘"htest"’ result, fixing PR#18901, thanks to Jesse Alderliesten.

• ‘R CMD check’ now handles archives with extension ‘.tar’ or ‘.tar.zstd’ (where ‘zstd’ compression is supported by the R build).

CHANGES IN R 4.2.0 NEW FEATURES

• ‘as.vector()’ gains a ‘data.frame’ method which returns a simple named list, also clearing a long-standing ‘FIXME’ to enable ‘as.vector(<data.frame>, mode="list")’. This breaks code relying on ‘as.vector(<data.frame>)’ to return the unchanged data frame.

• ‘R CMD check’ now handles archives with extension ‘.tar’ and ‘.tar.zstd’ (where ‘zstd’ compression is supported by the R build).

• .

CHANGES IN R 4.5.1 INSTALLATION

• Tcl/Tk 9 can be used to build package ‘tcltk’: this has become the default in some Linux distributions.

• The internal method of ‘unzip()’ now follows ‘unzip 6.00’ in how it handles extracted file paths which contain ‘"../"’. With thanks to Ivan Krylov.

• ‘prettyNum(*, zero.print={>=1-char}, replace.zero=TRUE)’ now works as documented, thanks to Marttila Mikko and Ivan Krylov's messages on R-devel.

• ‘pbeta(x, a,b, ..)’ for very large ‘a,b’ no longer returns ‘NaN’ but the correct values (0 or 1, or their logs for ‘log.p = TRUE’). This improves Mathlib's C level ‘bratio()’ and hence also ‘pnbinom()’, etc..

• Standalone ‘nmath’ can be built with early-2025 versions of ‘clang’-based compilers such as LLVM ‘clang’ 20, Apple ‘clang’ 17 and Intel ‘icx’ 2025.0.

• Tcl/Tk 9 can be used to build package ‘tcltk’: this has become the default in some Linux distributions. *N.B.* several third-party packages currently require Tcl/Tk 8 or even 8.6 without declaring so.

CHANGES IN R 4.5.1 BUG FIXES

• Java detection in ‘javareconf’ could not detect ‘libjvm.*’ in the ‘zero’ variant of the JDK (PR#18884). All valid variants as of JDK 24u are now supported.

• ‘factanal(.., rotation=*)’ now correctly updates ‘rotmat’, fixing PR#18886.

• ‘dnbinom(<large>, <muchlarger>, ..)’ now is ‘0’ correctly, instead of ‘NaN’ or ‘Inf’ sometimes.

• ‘dbinom(<large>, n=Inf, ..)’ is ‘0’ now correctly, instead of ‘NaN’ which also fixes many ‘dnbinom()’ cases, notably those mentioned in PR#16727 comment #5.

• Fixing C level “binomial deviance” ‘bd0()’ for extreme arguments (preventing under-/overflow) solves more PR#16727 cases and also prevents some full accuracy loss in such cases for ‘dbinom()’, ‘dnbinom()’, and via ‘dbinom_raw()’ potentially ‘dgeom()’, ‘dhyper()’, ‘dbeta()’, and ‘df()’.

• ‘signif(1.**e308, digits)’ no longer truncates unnecessarily (but still to prevent overflow to ‘Inf’), fixing PR#18889.

• Fixing C level “binomial deviance” ‘bd0()’ for extreme arguments (preventing under-/overflow) solves more PR#16727 cases and also prevents some full accuracy loss in such cases for ‘dbinom()’, ‘dnbinom()’, and via ‘dbinom_raw()’ potentially ‘dgeom()’, ‘dhyper()’, ‘dbeta()’, and ‘df()’.

• Standalone ‘nmath’ can be built with early-2025 versions of ‘clang’-based compilers such as LLVM ‘clang’ 20, Apple ‘clang’ 17 and Intel ‘icx’ 2025.0.

• Tcl/Tk 9 can be used to build package ‘tcltk’: this has become the default in some Linux distributions. *N.B.* several third-party packages currently require Tcl/Tk 8 or even 8.6 without declaring so.

CHANGES IN R 4.5.0 patched BUG FIXES

• Standalone ‘nmath’ can be built with early-2025 versions of ‘clang’-based compilers such as LLVM ‘clang’ 20, Apple ‘clang’ 17 and Intel ‘icx’ 2025.0.

• ‘dnbinom(<large>, <muchlarger>, ..)’ now is ‘0’ correctly, instead of ‘NaN’ or ‘Inf’ sometimes.

• ‘dbinom(<large>, n=Inf, ..)’ is ‘0’ now correctly, instead of ‘NaN’ which also fixes many ‘dnbinom()’ cases, notably those mentioned in PR#16727 comment #5.

• ‘signif(1.**e308, digits)’ no longer truncates unnecessarily (but still to prevent overflow to ‘Inf’), fixing PR#18889.

• ‘factanal(.., rotation=*)’ now correctly updates ‘rotmat’, fixing PR#18886.

• A C23 compiler (if available) is now selected by default for compilation of R and packages. R builds can opt out _via_ the ‘configure’ flag ‘--without-C23’, unless the specified or default (usually ‘gcc’) compiler defaults to C23: ‘gcc’ 15 does.

  A C23 compiler is known to be selected with ‘gcc’ 13-15, LLVM ‘clang’ 18-20 (and 15 should), Apple ‘clang’ 15-17 and Intel 2024.2-2025.0 (and 2022.2 should).

  Current binary distributions on macOS use Apple ‘clang’ 14 and so do not use C23.

• Java detection in ‘javareconf’ could not detect ‘libjvm.*’ in the ‘zero’ variant of the JDK (PR#18884). All valid variants as of JDK 24u are now supported.

• Standalone ‘nmath’ can be built with early-2025 versions of ‘clang’-based compilers such as LLVM ‘clang’ 20, Apple ‘clang’ 17 and Intel ‘icx’ 2025.0.

• R on Windows by default uses ‘pkg-config’ for linking against external libraries. This makes it easier to test R and packages with alternative toolchains (such as from Msys2, e.g., testing with LLVM and possibly with sanitizers). It also allows more significant Rtools updates within a single R minor release.

• The installer scripts for Windows have been tailored to Rtools45, an update of the Rtools44 toolchain. It is based on GCC 14. The experimental support for 64-bit ARM (‘aarch64’) CPUs is based on LLVM 19. R-devel and R 4.5.x are no longer maintained to be buildable using Rtools44 and it is advised to switch to Rtools45.

CHANGES IN R 4.5.0 C-LEVEL API

• The ‘Writing R Extensions’ Texinfo source now contains very experimental annotations for more clearly identifying the API status of C entry points. These annotations are used to produce indices for API, experimental API, and embedded API entry points in the rendered versions. This is very preliminary and may be dropped if a better approach emerges.

  Also for Fortran-callable entry points which are part of the API.

• ‘Sys.setLanguage()’ now works in an ‘LC_ALL=C R’ session on some platforms, warns about _some_ failures to change the language and gets an option related to these warning messages.

• ‘Sys.setLanguage()’ now warns about _some_ failures to change the language.

• Setting ‘attributes’ on primitive functions is deprecated now and already an error in the development version of R. Changing the ‘environment’ of a primitive does no longer happen and signals a warning.

• This update was mainly bug fixes but contained a barely documented major change. The set of BLAS routines had been unchanged since 1988, so throughout R's history. This update introduced new BLAS routines ‘dgemmtr’ and ‘zgemmtr’ which are now used by LAPACK routines. This means that BLAS implementations are no longer interchangeable.

CHANGES IN R 4.5.0 INSTALLATION on a UNIX-ALIKE

• A C23 compiler (if available) is now selected by default for compilation of R and packages. R builds can opt out _via_ the ‘configure’ flag ‘--without-C23’, unless the specified or default (usually ‘gcc’) compiler defaults to C23: ‘gcc’ 15 will.

  A C23 compiler is known to be selected with ‘gcc’ 13-15, LLVM ‘clang’ 18-20 (and 15 should), Apple ‘clang’ 15-17 and Intel 2024.2-2025.0 (and 2022.2 should).

  Current binary distributions on macOS use Apple ‘clang’ 14 and so do not use C23.

CHANGES IN R 4.5.0 C-LEVEL FACILITIES

• There are new functions ‘asRboolean’ and ‘asBool’, variants of ‘asLogical’ more suited to converting logical arguments to ‘Rboolean’ or to ‘bool’. They require a length-one input and throw an error if that evaluates to ‘NA’.

• Setting ‘attributes’ on primitive functions is deprecated now and already an error in the development version of R.

CHANGES IN R 4.4.3 BUG FIXES

• Setting ‘attributes’ on primitive functions is deprecated now and already an error in the development version of R.

• ‘selectMethod(f, ..)’ now keeps the function name if the function belongs to a group generic and the method is for the generic.

CHANGES IN R 4.5.0 INSTALLATION on a UNIX-ALIKE

• A C23 compiler (if available) is now selected by default for compilation of R and packages. R builds can opt out _via_ the ‘configure’ flag ‘--without-C23’, unless the specified or default (usually ‘gcc’) compiler defaults to C23: ‘gcc’ 15 does.

  A C23 compiler is known to be selected with ‘gcc’ 13-15 (as used on Windows), LLVM ‘clang’ 18-20 (and 15 should), Apple ‘clang’ 15-17 and Intel 2024.2-2025.0 (and 2022.2 should).

  Current binary distributions on macOS use Apple ‘clang’ 14 and so do not use C23.

CHANGES IN R 4.5.0 INSTALLATION on WINDOWS

• R on Windows by default uses pkg-config for linking against external libraries. This makes it easier to test R and packages with alternative toolchains (such as from Msys2, e.g., testing with LLVM and possibly with sanitizers). It also allows more significant Rtools updates within a single R minor release.

• The installer scripts for Windows have been tailored to Rtools45, an update of the Rtools44 toolchain. It is based on GCC 14. The experimental support for 64-bit ARM (‘aarch64’) CPUs is based on LLVM 19. R-devel is no longer maintained to be buildable using Rtools44 and it is advised to switch to Rtools45.

CHANGES IN R 4.5.0 BUG FIXES

• ‘factanal()’ now works correctly also, e.g., for ‘GPArotation’, ‘oblimin()’ rotations, fixing PR#18417, thanks to Coen Bernaards and others.

• Defining ‘R_INCLUDE_BOOLEAN_H’ to ‘0’ before including headers ‘R.h’ or ‘Rinternals.h’ (or any other header which includes ‘R_ext/Boolean.h’) stops the inclusion of header ‘R_ext/Boolean.h’ which `defines' constants ‘TRUE’, ‘FALSE’, ‘true’, ‘false’ and the type ‘bool’ which some package maintainers wish to avoid.

  Note that the last three are keywords in C23 and C++11 so cannot be avoided entirely. However, with commonly-used compilers they can be masked by a macro of the same name, often with a warning.

• ‘model.frame()’ produces more informative error messages in some cases when variables in the formula are not found, thanks to Ben Bolker's PR#18860.

• ‘selectMethod(f, ..)’ now keeps the function name if the function belongs to of a group generic and the method is for the generic.

CHANGES IN R 4.4.3 BUG FIXES

• Setting ‘attributes’ on primitive functions is deprecated now and already an error in the development version of R.

• Defining ‘R_INCLUDE_BOOLEAN_H’ to ‘0’ before including headers ‘R.h’ or ‘Rinternals.h’ (or any other header which includes ‘R_ext/Boolean.h’) stops the inclusion of header ‘R_ext/Boolean.h’ which `defines' constants ‘TRUE’, ‘true’, ‘false’ and the type ‘bool’ which some package maintainers wish to avoid.

  Note that the last three are keywords in C23 and C++11 so cannot be avoided entirely. However, with commonly-used compilers they can be masked by a macro of the same name, often with a warning.

• ‘isSymmetric(<matrix>)’ gains a new option ‘trans = "C"’; when set to non-default, it tests for “simple” symmetry of complex matrices.

• ‘R CMD check’ now also reports bad symbols in package shared objects linked in from local static libraries (PR#18789).

• Building with the bundled (and old) version of ‘libintl’ is deprecated and now gives a ‘configure’ warning. This should be selected only if neither the OS's ‘libc’ (as on GNU Linux) nor an external ‘libintl’ library provide suitable functions.

  Instead install ‘libintl’ from a recent version of GNU gettext (available for macOS) or use ‘configure’ option ‘--disable-nls’.

  The ability to use the bundled version may be removed as soon as R 4.5.1.

CHANGES IN R 4.5.0 UTILITIES

• ‘R CMD check’ gains option ‘--run-demo’ to check demo scripts analogously to tests. This includes a check for undeclared package dependencies: it can also be enabled separately by setting the environment variable ‘_R_CHECK_PACKAGES_USED_IN_DEMO_’ to a true value (as done by ‘R CMD check --as-cran’).

• Header ‘R_exts/Utils.h’ no longer contains a declaration for ‘F77_SUB(interv)’. This is intended to be called from Fortran and was wrongly declared: ‘LOGICAL’ in Fortran corresponds to ‘int *’ not ‘Rboolean *’.

CHANGES IN R 4.5.0 BUG FIXES

• ‘trace(coerce, ..)’ now works correctly, fixing PR#18823 thanks to Mikael Jagan.

• R on Windows by default uses pkg-config for linking against external libraries. This makes it easier to test R and packages with alternative toolchains (such as from Msys2, e.g. testing with LLVM and possibly with sanitizers). It also allows more significant Rtools updates within a single R minor release.

• The installer scripts for Windows have been tailored to Rtools45, an update of the Rtools44 toolchain. It is based on GCC 14. The experimental support for 64-bit ARM (aarch64) CPUs is based on LLVM 19. R-devel is no longer maintained to be buildable using Rtools44 and it is advised to switch to Rtools45.

• ‘as.integer(rl)’ and hence ‘as.raw(rl)’ now work for a ‘list’ of ‘raw(1)’ elements, as proposed by Michael Chirico's PR#18696.

• ‘graphics’' ‘grid()’ gains optional argument ‘nintLog’.

• New functions ‘check_package_urls()’ and ‘check_package_dois()’ in package ‘tools’ for checking URLs and DOIs in package sources.

• New ‘head()’ and ‘tail()’ methods for class ‘"ts"’ time series, proposed by Spencer Graves on R-devel.

• New ‘qr.influence()’ function, a “bare bones” interface to the ‘lm.influence()’ leave-one-out diagnostics computations; wished for in PR#18739.

• Package ‘citation()’ results auto-generated from the package metadata now also provide package DOIs for CRAN and Bioconductor packages.

• New function ‘grepv()’ identical to ‘grep()’ except for the default ‘value = TRUE’.

• ‘methods(<pkg>:::<genfun>)’ now does report methods when neither the generic nor the methods have been exported.

• ‘pdf()’ gains an ‘author’ argument to set the corresponding metadata field, and logical arguments ‘timestamp’ and ‘producer’ to optionally omit the respective metadata. (Thanks to Edzer Pebesma.)

• ‘grDevices::glyphInfo()’ gains a ‘rot’ argument to allow per-glyph rotation. (Thanks to Daniel Sabanes Bove.)

• Package ‘tools’ now exports functions ‘CRAN_current_db()’, ‘CRAN_aliases_db()’, ‘CRAN_rdxrefs_db()’, ‘CRAN_archive_db()’, and ‘CRAN_authors_db()’.

• Package ‘tools’ now exports functions ‘R()’ and ‘parse_URI_reference()’.

• Package ‘tools’ now exports functions ‘base_aliases_db()’ and ‘base_rdxrefs_db()’.

• It is now possible to set the background color for row and column names in the data editor on Windows (‘Rgui’).

• ‘Rterm’ on Windows now accepts input lines of unlimited length.

• ‘file.info()’ on Windows now provides file owner name and domain.

• ‘Sys.info()’ on Windows now provides current user domain.

• ‘findInterval()’ gets new arguments ‘checkSorted’ and ‘checkNA’ which allow skipping relatively costly checks; related to PR#16567.

• ‘pnorm(x)’ underflows more gracefully.

• ‘get(nam, env)’ now signals a _classed_ error, ‘"getMissingError"’, as “subclass” of ‘"missingArgError"’ where the latter is used also in similar situations, e.g., ‘f <- function(x) exp(x); try(f())’ .

• The set operations now avoid the ‘as.vector()’ transformation for same-kind apparently vector-like operands.

• ‘md5sum()’ can be used to compute an MD5 hash of a raw vector of bytes by using the ‘bytes=’ argument instead of ‘files=’. The two arguments are mutually exclusive.

• Added function ‘sha256sum()’ in package ‘tools’ analogous to ‘md5sum()’ implementing the SHA-256 hashing algorithm.

• The ‘xtfrm()’ method for class ‘"AsIs"’ is now considerably faster thanks to a patch provided by Ivan Krylov.

• The ‘merge()’ method for data frames will no longer convert row names used for indexing using ‘I()’, which will lead to faster execution in cases where ‘sort = TRUE’ and ‘all.x’ and/or ‘all.y’ are set to ‘TRUE’.

• The ‘methods’ package internal function ‘.requirePackage()’ now calls ‘requireNamespace(p)’ instead of ‘require(p)’, hence no longer adding packages to the ‘search()’ path in cases methods or class definitions are needed. Consequently, previous workflows relying on the old behaviour will have to be amended by adding corresponding ‘library(p)’ calls.

• More R-level messages use a common format containing ‘"character string"’ for more consistency and less translation work.

• ‘available.packages()’ and ‘install.packages()’ get an optional switch ‘cache_user_dir’, somewhat experimentally.

• The ‘sunspot.month’ data have been updated to Oct 2024; because of recalibration also historical numbers are changed, and we keep the previous data as ‘sunspot.m2014’ for reproducibility.

• The ‘quartz()’ device now supports alpha masks. Thanks to George Stagg, Gwynn Gebeyhu, Heather Turner, and Tomek Gieorgijewski.

• The ‘print()’ method for date-time objects (‘POSIX.t’) gets an optional ‘digits’ argument for _fractional_ seconds, passed to improved ‘format.POSIXlt()’; consequently, ‘print(<date.time>, digits = n)’ allows to print fractions of seconds.

• ‘install.packages()’ and ‘download.packages()’ download packages simultaneously using ‘libcurl’, significantly reducing download times when installing or downloading multiple packages.

• Status reporting in ‘download.file()’ has been extended to report the outcome for individual files in simultaneous downloads.

• The Rd \link macro now allows markup in the link text when the topic is given by the optional argument, e.g., ‘\link[=gamma]{\eqn{\Gamma(x)}}’.

• If ‘La_library()’ is empty, ‘sessionInfo()’ still reports ‘La_version()’ when available.

• ‘seq.int(from, to, by, ....)’ when |by| = 1 now behaves as if ‘by’ was omitted, and hence returns ‘from:to’, possibly integer.

• ‘seq.Date(from, to, by, ....)’ and ‘seq.POSIXt(..)’ now also work when ‘from’ is missing and sufficient further arguments are provided, thanks to Michael Chirico's report, patch proposal in PR#17672 and ‘R Dev Day’ contributions.

  The ‘Date’ method also works for ‘seq(from, to)’, when ‘by’ is missing and now defaults to ‘"1 days"’.

  It is now documented (and tested) that the ‘by’ string may be _abbreviated_ in both ‘seq’ methods.

  Both methods return or keep internal type ‘"integer"’ more consistently now. Also, ‘as.POSIXct({})’ is internally integer.

• ‘duplicated()’, ‘unique()’, and ‘anyDuplicated()’ now also work for class ‘expression’ vectors.

• New function ‘use()’ to use packages in R scripts with full control over what gets added to the search path. (Actually already available since R 4.4.0.)

• There is some support for ‘zstd’ compression of tarballs in ‘tar()’ and ‘untar()’. (This depends on OS support of ‘libzstd’ or by ‘tar’.)

• ‘print(summary(<numbers>))’ gets new optional argument ‘zdigits’ to allow more flexible and consistent (double) rounding. The current default ‘zdigits = 4L’ is somewhat experimental. Specifying both ‘digits = *, zdigits = *’ allows behaviour independent of the global ‘digits’ option.

• The ‘format()’ method for ‘"difftime"’ objects gets a new back compatible option ‘with.units’.

• A ‘summary()’ method for ‘"difftime"’ objects which prints nicely, similar to those for ‘"Date"’ and ‘"POSIXct"’.

• ‘unique()’'s default method now also deals with ‘"difftime"’ objects.

• ‘optimize(f, *)’ when ‘f(x)’ is not finite says more about the value in its ‘warning’ message. It no longer replaces ‘-Inf’ by the largest _positive_ finite number.

• The documentation of ‘gamma()’ and ‘is.numeric()’ is more specific, thanks to the contributors of PR#18677.

• New dataset ‘gait’ thanks to Heather Turner and Ella Kaye, used in examples.

• New datasets ‘penguins’ and ‘penguins_raw’ thanks to Ella Kaye, Heather Turner, and Kristen Gorman.

CHANGES IN R 4.5.0 BLAS and LAPACK

• The bundled BLAS and LAPACK sources have been updated to those shipped as part of January 2025's LAPACK 3.12.1.

• It is intended that this will be the last update to BLAS and LAPACK in the R sources. Those building R from source are encouraged to use external BLAS and LAPACK and this will be required in future.

• This update was mainly bug fixes but contained a barely documented major change. The set of BLAS routines has been unchanged since 1988, so throughout R's history. This update introduced new BLAS routines ‘dgemmtr’ and ‘zgemmtr’ which are now used by LAPACK routines. This means that BLAS implementations are no longer interchangeable.

• To work around this, R can be configured with option ‘--with-2025blas’ which arranges for the 2025 BLAS additions to be compiled into ‘libRlapack’ (the internal LAPACK, not built if an external LAPACK is used).

  This option allows the continuation of the practice of swapping the BLAS in use by symlinking ‘lib/libRblas.*’. It has the disadvantage of using the reference BLAS version of the 2025 routines whereas an enhanced BLAS might have an optimized version (OpenBLAS does as from version 0.3.29).

• Windows builds currently use the internal LAPACK and by default the internal BLAS: notes on how to swap the latter _via_ ‘Rblas.dll’ are in file ‘src/extra/blas/Makefile.win’.

CHANGES IN R 4.5.0 INSTALLATION on a UNIX-ALIKE

• A C23 compiler (if available) is now selected by default for compilation of R and packages. R builds can opt out _via_ the ‘configure’ flag ‘--without-C23’, unless the specified or default (usually ‘gcc’) compiler defaults to C23: ‘gcc’ 15 does.

  A C23 compiler is known to be selected with ‘gcc’ 13-15 (as used on Windows), LLVM ‘clang’ 18-20 (and 15 should), Apple ‘clang’ 15-16 and Intel 2024.2 (and 2022.2 should).

  Current binary distributions on macOS use Apple ‘clang’ 14 and so do not use C23.

• The minimum ‘autoconf’ requirement for a maintainer build has been increased to ‘autoconf’ 2.72.

• Building the HTML and Info versions of the R manuals now requires ‘texi2any’ from Texinfo 6.1 or later.

• Failures in building the manuals under ‘doc’ now abort the installation, removing any file which caused the failure.

• Control of symbol visibility is now supported on macOS (the previous check only worked on ELF platforms).

• There is now support for installing the debug symbols for recommended packages on macOS: see ‘REC_INSTALL_OPT’ in file ‘config.site’.

• ‘configure’ is now able to find an external ‘libintl’ on macOS (the code from an older GNU gettext distribution failed to try linking with the macOS Core Foundation framework).

CHANGES IN R 4.5.0 INSTALLATION on WINDOWS

• Both building R and installing packages use the C compiler in C23 mode.

CHANGES IN R 4.5.0 DEPRECATED AND DEFUNCT

• ‘is.R()’ is defunct. Environment variable ‘_R_DEPRECATED_IS_R_’ no longer has any effect.

• Deprecated (for more than 9 years!) functions ‘linearizeMlist’, ‘listFromMlist’, and ‘showMlist’ and the ‘"MethodsList"’ class for S4 method handling were removed from package ‘methods’. Deprecated functions ‘balanceMethodsList’, ‘emptyMethodsList’, ‘inheritedSubMethodLists’, ‘insertMethod’, ‘insertMethodInEmptyList’, ‘makeMethodsList’, ‘mergeMethods’, ‘MethodsList’, ‘MethodsListSelect’, and ‘SignatureMethod’ were made defunct, as were the ‘"MethodsList"’ branches of functions ‘assignMethodsMetaData’, ‘finalDefaultMethod’, and ‘MethodAddCoerce’.

• ‘getMethods(*, table = TRUE)’ is deprecated.

• Building with the bundled (and old) version of ‘libintl’ is deprecated and now gives a ‘configure’ warning. This should be selected only if neither the OS's ‘libc’ (as on GNU Linux) nor an external ‘libintl’ library (as on Alpine Linux) provide suitable functions.

  Instead install ‘libintl’ from a recent version of GNU gettext or use ‘configure’ option ‘--disable-nls’.

• The deprecated ‘xfig()’ graphics device has been removed.

CHANGES IN R 4.5.0 PACKAGE INSTALLATION

• Packages are now installed using C23 where supported by the OS and R build.

  Packages using R's compiler settings can ask *not* to use C23 _via_ including ‘USE_C17’ in ‘SystemRequirements’ or can be installed by ‘R CMD INSTALL --use-C17’. (Some packages ignore these settings in their ‘configure’ script or when compiling in sub-directories of ‘src’, as will those using a ‘src/Makefile’.)

• Source installs now report the package version in the log.

• There is preliminary support for C++26 with GCC >= 14, Apple ‘clang++’ >= 16 and LLVM ‘clang++’ >= 17.

CHANGES IN R 4.5.0 C-LEVEL FACILITIES

• The non-API and hidden entry points ‘Rf_setIVector’, ‘Rf_setRVector’ and ‘Rf_setSVector’ have been removed.

• The internal code for changing the parent of an environment now signals an error if the new parent is not an environment or if the change would create a cycle in the parent chain.

• ‘SET_TYPEOF’ now signals an error unless the old and new types have compatible memory structure and content. Use of ‘SET_TYPE’ in package C code should be avoided and may be deprecated in the near future. It is better to allocate an object of the desired type in the first place.

• The set of LAPACK (double and complex) routines declared in the headers ‘R_ext/Lapack.h’ and ‘R_ext/Applic.h’ has been extended, mostly to routines actually in use by packages.

• Memory allocation messages now use the (non-SI notation) ‘"Mb"’, ‘"Gb"’ , ..., and ‘"Mbytes"’ strings as _arguments_ instead of as part of the (translatable format) string. This is one step for PR#18297; from Henrik Bengtsson.

• Header ‘R_ext/Constants.h’ (included by ‘R.h’) now always includes header ‘float.h’ or ‘cfloat’ for constants such as ‘DBL_MAX’.

• Strict R headers are now the default. This removes the legacy definitions of ‘PI’, ‘Calloc’, ‘Realloc’ and ‘Free’: use ‘M_PI’, ‘R_Calloc’, ‘R_Realloc’ or ‘R_Free’ instead.

• The deprecated and seemingly never-used S-compatibility macros ‘F77_COM’ and ‘F77_COMDECL’ have been removed from header ‘R_ext/RS.h’.

• The ‘enum’ ‘Rboolean’ defined in header ‘R_ext/Boolean.h’ now has a fixed underlying type of ‘int’ on platforms whose C compiler supports this.

  This is a C23 feature (taken from C++11) and also supported in all C standards by some versions of ‘clang’ (from LLVM and Apple) and (with a warning when using ‘-pedantic’) by GCC when in C17 mode.

  A fair amount of code has assumed this: it may be changed to a smaller type in future. In particular, as standard compilers do not check the validity of assignment to an ‘enum’, it has been possible to assign ‘NA_INTEGER’ to an ‘Rboolean’ variable, coerce it to ‘int’ and recover the value.

  If there were a platform which used an underlying type of a different size this would be an ABI-breaking change (but we are unaware of any such platform).

• Header ‘R_ext/Boolean.h’ now ensures that a ‘bool’ type is available either as a keyword (C23 and C++) or by including the C99 header ‘stdbool.h’. This is being used internally in R to replace ‘Rboolean’ by ‘bool’.

• There are a new functions ‘asRboolean’ and ‘asBool’, variants of ‘asLogical’ more suited to converting logical arguments to ‘Rboolean’ or to ‘bool’. They require a length-one input and throw an error if that evaluates to ‘NA’.

• Header ‘R_exts/Error.h’ now ensures that ‘Rf_error’ and similar are given a ‘noreturn’ attribute when used from C++ under all compilers.

• Header ‘R_exts/Utils.h’ no longer contains a declaration for ‘77_SUB(interv)’. This is intended to be called from Fortran and was wrongly declared: ‘LOGICAL’ in Fortran corresponds to ‘int *’ not ‘Rboolean *’.

CHANGES IN R 4.5.0 C-LEVEL API

• The ‘Writing R Extensions’ Texinfo source now contains very experimental annotations for more clearly identifying the API status of C entry points. These annotations are used to produce indices for API, experimental API, and embedded API entry points in the rendered versions. This is very preliminary and may be dropped if a better approach emerges.

  Also now for Fortran-callable entry points which are part of the API.

• ‘Writing R Extensions’ has a new section ‘Moving into C API compliance’ to help package authors move away from using non-API endpoints. This section will continue to be updated as work on clarifying and tightening the C API continues.

• New API function ‘R_mkClosure’. This checks that its arguments are valid and should be used instead of ‘allocSExp(CLOSXP’ followed by ‘SET_FORMALS’, ‘SET_BODY’, and ‘SET_CLOENV’.

• New API functions ‘R_ClosureFormals’, ‘R_ClosureBody’, and ‘R_ClosureEnv’ for extracting closure components. The existing functions ‘R_ClosureExpr’ and ‘R_BytecodeExpr’ have also been added to the API.

• New API function ‘R_ParentEnv’ corresponding to R's ‘parent.env()’.

• Further non-API entry points have been added to those reported by ‘R CMD check’: ‘COMPLEX0’, ‘ddfind’, ‘DDVAL’, ‘ENSURE_NAMEDMAX’, ‘ENVFLAGS’, ‘FRAME’, ‘HASHTAB’, ‘INTERNAL’, ‘IS_ASCII’, ‘IS_UTF8’, ‘LEVELS’, ‘NAMED’, ‘PRSEEN’, ‘RDEBUG’, ‘REAL0’, ‘Rf_findVarInFrame3’, ‘SET_BODY’, ‘SET_CLOENV’, ‘SET_FORMALS’, ‘SET_PRSEEN’, ‘SET_RDEBUG’, ‘STRING_PTR’, ‘SYMVALUE’, and ‘VECTOR_PTR’. Any declarations for these in public header files will be removed in the near future, and they will be hidden where possible.

• Some ‘R CMD check’ ‘NOTE’s on the use of non-API entry points have been upgraded to ‘WARNING’s in preparation for removing declarations and, where possible, hiding these entry points.

• Additional non-API entry points have been added to those reported by ‘R CMD check’: ‘IS_LONG_VEC’, ‘PRCODE’, ‘PRENV’, ‘PRVALUE’, ‘R_nchar’, ‘Rf_NonNullStringMatch’, ‘R_shallow_duplicate_attr’, ‘Rf_StringBlank’, ‘SET_TYPEOF’, ‘TRUELENGTH’, ‘XLENGTH_EX’, and ‘XTRUELENGTH’.

• Enable defining ‘R_NO_REMAP_RMATH’ and calling ‘Rf_*()’ as has been documented in ‘Writing R Extensions’ for a while, fixing PR#18800 thanks to Mikael Jagan and Suharto Anggono.

• ‘R_GetCurrentSrcref(skip)’ now skips calls rather than ‘srcref’s, consistent with counting items in the ‘traceback()’ display. If ‘skip == NA_INTEGER’, it searches for the first ‘srcref’, starting at the current evaluation state and proceeding through the call stack; otherwise, it returns the ‘srcref’ of the requested entry from the call stack.

CHANGES IN R 4.5.0 UTILITIES

• ‘R CMD INSTALL’ (and hence ‘check’) now compile C++ code with ‘-DR_NO_REMAP’.

  ‘Writing R Extensions’ has been revised to describe the remapped entry points, for with the ‘Rf_’ prefix remains optional when used from C code (but is recommended for new C code).

• ‘R CMD check --as-cran’ notes bad parts in the ‘DESCRIPTION’ file's URL fields.

• ‘R CMD check’ now reports more warnings on long-deprecated/obsolete Fortran features reported by ‘gfortran -Wall’. For hints on how to modernize these, see <https://fortranwiki.org/fortran/show/Modernizing+Old+Fortran>.

• Since almost all supported R versions now use UTF-8, ‘R CMD check’ no longer by default reports on marked UTF-8 or Latin-1 strings in character data. Set environment variable ‘_R_CHECK_PACKAGE_DATASETS_SUPPRESS_NOTES_’ to a false value for the previous behaviour.

• ‘tools::checkDocFiles()’ notes more cases of usage documentation without corresponding \alias.

• ‘R CMD check’ with a true value for environment variable ‘_R_CHECK_BASHISMS_’ checks more thoroughly, including for ‘bash’ scripts and bashisms in components of ‘autoconf’-generated ‘configure’ scripts.

• ‘R CMD check’ gains option ‘--run-demo’ to check demo scripts analogously to tests.

• ‘R CMD build’ now supports ‘--compression=zstd’ on platforms with sufficient support for ‘zstd’.

• ‘tools::texi2pdf(..., texinputs=<paths>)’ now _pre_pends the specified <paths> to ‘TEXINPUTS’. When building R itself (‘doc/NEWS.pdf’ and base vignettes) or package manuals using ‘R CMD Rd2pdf’, it is ensured that this R's ‘Rd.sty’ takes precedence over any other (incompatible) versions in default “texmf trees”.

• ‘tools::Rd2latex()’ no longer outputs an ‘\inputencoding{utf8}’ line by default; such a declaration is obsolete since LaTeX 2018-04-01.

CHANGES IN R 4.5.0 BUG FIXES

• ‘update_pkg_po()’ now copies ‘.mo’ files to the ‘translation’ package even if a ‘DESCRIPTION’ file exists, thanks to Michael Chirico fixing PR#18694.

• Auto-generated ‘citation()’ entries no longer include (additional) URLs in the ‘note’ field (PR#18547).

• ‘as.data.frame.list()’ gets a new option ‘new.names’ and now preserves ‘NA’ names, thus fixing the ‘format()’ method for data frames, and also bug PR#18745. Relatedly, the ‘format()’ method gets an option ‘cut.names’.

• ‘stem()’ formats correctly also in cases where rounding up, e.g., from 9.96 to 10 needs more digits; thanks to Ella Kaye and Kelly Bodwin, fixing PR#8934 during ‘R Dev Day’ at useR!2024.

  Additionally, ‘stem(x)’ now works normally also when ‘length(x) == 1’.

• ‘tools’' ‘toTitleCase()’ now works better, fixing PR#18674, thanks to Shannon Pileggi, Sarah Zeller, Reiko Okamoto, and Hugo Gruson's ‘R Dev Day’ effort.

• Printing matrices (typically with many rows and or columns) now also omits columns when desirable according to option ‘max.print’, or argument ‘max’, respectively. This is primarily the work of Lorena Abad, Ekaterina Akimova, Hanne Oberman, Abhishek Ulayil, and Lionel Henry at the ‘R Dev Day’, thus fixing PR#15027.

• ‘Sys.setLanguage()’ now works in an ‘LC_ALL=C R’ session on some platforms, warns about _some_ failures to change the language and gets an option related to these warning messages.

• Printing ‘ls.str()’ now shows ‘"<missing>"’ even when R's language setting is not English.

• ‘xyTable()’ now handles and reports ‘NA’s fixing PR#18654. Thanks to Heather Turner and Zhian Kamvar for report and patch.

• ‘as(*, "raw")’ now works as documented, thanks to Mikael Jagan's PR#18795.

• Informational messages of e.g., ‘print(1:1e4, max=1000)’, now correctly mention ‘max’ in addition to ‘getOption("max.print")’.

• ‘rowSums(A, dims = dd)’, ‘colMeans(..)’, etc, give a more helpful error message when ‘dd’ is not of length one, thanks to Michael Chirico's PR#18811.

• ‘seq.Date()’ no longer explicitly coerces results from integer to double, analogously with ‘seq.default()’, ‘seq.int()’ and ‘seq.POSIXt()’, resolving a _modified_ PR#18782.

• ‘axisTicks(usr, ...)’ documentation clarification for ‘log = TRUE’, fixing bug PR#18821 thanks to Duncan Murdoch.

• ‘debug()’ and ‘debugonce(fun)’ now also accept a string ‘fun’ when it names an S4 generic, fixing PR#18822 thanks to Mikael Jagan.

• ‘debugonce(<S4-simple-body>, signature=*)’ now works correctly when “called twice”, fixing PR#18824 thanks to Mikael Jagan.

• ‘format(dtime, digits=* / format=*)’ is more consistent when the ‘POSIXt’ date-time object ‘dtime’ has fractional (non integer) seconds. Fixes PR#17350, thanks to new contributions by LatinR's ‘R Dev Day’ participants, Heather Turner and Dirk Eddelbuettel; also fixes more cases, notably when ‘format’ contains "

• ‘options(scipen = NULL)’ and other invalid values now signal an error instead of invalidating ops relying on a finite integer value. Values outside the range -9 .. 9999 are now warned about and set to a boundary or to the default ‘0’, e.g., in case of an ‘NA’.

• ‘cbind()’ could segfault with ‘NULL’ inputs. (Seen when R was built with ‘gcc-14’, LTO and C99 inlining semantics.)

• Fix segfault on ‘quartz()’ from ‘grid.glyph()’ call with ‘glyphInfo()’ that describes non-existent font (PR#18784). Thanks to Tomek Gieorgijewski.

• ‘format()’ etc, using ‘decimal.mark = s’, by default getting ‘s <- getOption("OutDec")’, signals a warning (to become an error in the future) when ‘s’ is not a string with exactly one character.

• When ‘s <- getOption("OutDec")’ is not a string of one character, a warning is signalled now whenever it is used in internal C code, notably when calling the default methods of ‘format()’.

• ‘pwilcox()’ and ‘qwilcox()’ now check for user interrupt less frequently.

• ‘summary(<stl>)’ (which prints directly) finally gets the same ‘digits’ default as the formatting printing of default ‘summary()’ method results, and it is documented explicitly.

• ‘options(show.error.locations = TRUE)’ once again shows the most recent known location when an error is reported. Setting its value to ‘"bottom"’ is no longer supported. Numerical values are converted to logical.

• C API function ‘R_GetCurrentSrcref(skip)’ now returns ‘srcref’ entries correctly. (Note that there is also a change to the interpretation of ‘skip’; see the C-LEVEL API entry above.)

• ‘tools::Rd2latex()’ now removes leading and trailing spaces from \alias entries as documented, fixing indexing and linking hiccups in some PDF manuals.

• ‘R CMD Rd2pdf’ can now render the package manual from a ‘--latex’ installation also when the help contains figures.

• The argument of ‘as.environment()’ is now named ‘x’, not ‘object’, as was always documented and shown when printing it; thanks to Gael Millot's PR#18849.

• When ‘R CMD check’ aims at getting the time+date from a world clock, it is more robust against unexpected non-error results, thanks to Michael Chirico's PR#18852.

• The ‘tools::parseLatex()’ parser made several parsing errors (PR#18855).

• Error messages produced by ‘tools::parseLatex()’ are now more readable (PR#18855).

• ‘R CMD build <pkg>’ excludes more file patterns when it tars the <pkg> directory, fixing both PR#18432 and PR#18434, for ‘vim’ and ‘GNU Global’ ‘emacs’ users, thanks to Dirk Eddelbuettel's patch.

• ‘quantile()’'s default method gets an option ‘fuzz’ to protect against floating point inaccuracy before rounding, thus fixing PR#15811 and, en passant, PR#17683.

• Printing arrays now also omits columns, rows and slices when desirable according to option ‘max.print’, or argument ‘max’, respectively, addressing most of the remaining part of PR#15027, thanks to Sherry Zhang's patch.

• ‘drop.terms(y ~ w, 1)’ and similar now work, thanks to Benjamin Sommer's report in PR#18861 and collaboration with Heather Turner improving ‘reformulate()’.

• Many arguments which should be length-1 logical are checked more thoroughly. The most commonly seen errors are in ‘unlink(, recursive)’, ‘tempdir()’ and the ‘na.rm’ arguments of ‘max()’, ‘min()’, ‘sum()’, ....

  ‘grep()’, ‘strsplit()’ and similar took non-‘TRUE’/‘FALSE’ values of their logical arguments as ‘FALSE’, but these were almost always mismatches to unnamed arguments and are now reported as ‘NA’.

• ‘vignette("reshape")’ is now also available on Windows.