This blog is updated daily.
A general description is here.
Argument ‘compressed’ of ‘untar()’ is deprecated - it is only used for externsal ‘tar’ commands which increasingly for extraction auto-detect compression and ignore their ‘zjJ’ flags.
Serialization format version 3 becomes the default for serialization and saving of the workspace (‘save()’, ‘serialize()’, ‘saveRDS()’, ‘cmpfile()’). Serialized data in format 3 cannot be read by versions of R prior to version 3.5.0. Serialization format version 2 is still supported and can be selected by ‘version = 2’ in the save/serialization functions. The default can be changed back for the whole R session by setting environment variables ‘R_DEFAULT_SAVE_VERSION’ and ‘R_DEFAULT_SERIALIZE_VERSION’ to ‘2’. For maximal back-compatibility, files ‘vignette.rds’ and ‘partial.rdb’ generated by ‘R CMD build’ are in serialization format version 2, and resave by default produces files in serialization format version 2 (unless the original is already in format version 3).
The new functions ‘mem.maxVSize()’ and ‘mem.maxMSize()’ allow the maximal size of the vector heap and the maximal number of nodes allowed in the current ‘R’ process to be queried and set.
An effort has been started to have our reference manuals, i.e., all help pages. show platform-independent information (rather than Windows or Unix-alike specifics visible only on that platform).
‘untar()’ used with an external ‘tar’ command assumes this supports decompression including ‘xz’ and automagically detecting the compression type. This has been true of all mainstream implementations since 2009 (for GNU ‘tar’, since version 1.22): older implementations are still supported _via_ the new argument ‘support_old_tars’ whose default is controlled by environment variable ‘R_SUPPORT_OLD_TARS’. (It looks like NetBSD and OpenBSD have ‘older’ ‘tar’ for this purpose.)
‘untar()’ ignored a character ‘compressed’ argument: however many external ‘tar’ programs ignore the flags which should have been set and automagically choose the compression type, and if appropriate ‘gzip’ or ‘bzip2’ compression would have been chosen from the magic header of the tarball.