--- /dev/null
- ** The new configure option '--with-json' adds support for JSON using
- the Jansson library. It is on by default; use './configure
- --with-json=no' to build without Jansson support. The new JSON
- functions 'json-serialize', 'json-insert', 'json-parse-string', and
- 'json-parse-buffer' are typically much faster than their Lisp
- counterparts from json.el.
+GNU Emacs NEWS -- history of user-visible changes.
+
+Copyright (C) 2017-2019 Free Software Foundation, Inc.
+See the end of the file for license conditions.
+
+Please send Emacs bug reports to 'bug-gnu-emacs@gnu.org'.
+If possible, use 'M-x report-emacs-bug'.
+
+This file is about changes in Emacs version 27.
+
+See file HISTORY for a list of GNU Emacs versions and release dates.
+See files NEWS.26, NEWS.25, ..., NEWS.18, and NEWS.1-17 for changes
+in older Emacs versions.
+
+You can narrow news to a specific version by calling 'view-emacs-news'
+with a prefix argument or by typing 'C-u C-h C-n'.
+
+Temporary note:
++++ indicates that all relevant manuals in doc/ have been updated.
+--- means no change in the manuals is needed.
+When you add a new item, use the appropriate mark if you are sure it
+applies, and please also update docstrings as needed.
+
+\f
+* Installation Changes in Emacs 27.1
+
++---
+** Emacs now uses GMP, the GNU Multiple Precision library.
+By default, if 'configure' does not find a suitable libgmp, it
+arranges for the included mini-gmp library to be built and used.
+The new 'configure' option '--without-libgmp' uses mini-gmp even if a
+suitable libgmp is available.
+
++---
+** Emacs can now use HarfBuzz as its shaping engine.
+The new configure option '--with-harfbuzz' adds support for the
+HarfBuzz text shaping engine. It is on by default; use './configure
+--without-harfbuzz' to build without it. The HarfBuzz text shaping is
+available via new font backend drivers 'xfthb' and 'ftcrhb' for Xft
+and Cairo drawings, respectively, and via the 'harfbuzz' backend on
+MS-Windows. The Harfbuzz text shaping is preferred to the previously
+supported ones, so the font backends that use older shaping engines
+(FLT on GNU and Unix systems and Uniscribe on MS-Windows) are not
+enabled by default; they can be enabled via the 'font-backend' frame
+parameter or via X resources.
+
- when Emacs is built with GTK+.
-
- ** Emacs no longer defaults to using ImageMagick to display images,
- due to security and stability concerns. To override the default, use
- 'configure --with-imagemagick'.
-
- ** Several configure options now accept an option-argument 'ifavailable'.
- For example, './configure --with-xpm=ifavailable' now configures Emacs
- to attempt to use libxpm but to continue building even if libxpm is
- absent. The other affected options are '--with-gif', '--with-gnutls',
- '--with-jpeg', '--with-png', and '--with-tiff'.
-
- ** The etags program now uses the C library's regular expression matcher
- when possible, and a compatible regex substitute otherwise. This will
- let developers maintain Emacs's own regex code without having to also
- support other programs. The new configure option '--without-included-regex'
- forces etags to use the C library's regex matcher even if the regex
- substitute ordinarily would be used to work around compatibility problems.
-
- ** Emacs has been ported to the '-fcheck-pointer-bounds' option of GCC.
- This causes Emacs to check bounds of some arrays addressed by its
- internal pointers, which can be helpful when debugging the Emacs
- interpreter or modules that it uses. If your platform supports it you
- can enable it when configuring, e.g., './configure CFLAGS="-g3 -O2
- -mmpx -fcheck-pointer-bounds"' on Intel MPX platforms.
-
- ** Emacs now normally uses a C pointer type instead of a C integer
- type to implement Lisp_Object, which is the fundamental machine word
- type internal to the Emacs Lisp interpreter. This change aims to
- catch typos and supports '-fcheck-pointer-bounds'. The 'configure'
- option '--enable-check-lisp-object-type' is therefore no longer as
- useful and so is no longer enabled by default in developer builds,
- to reduce differences between developer and production builds.
++---
++** The new configure option '--with-json' adds native support for JSON.
++This uses the Jansson library. The option is on by default; use
++'./configure --with-json=no' to build without Jansson support. The
++new JSON functions 'json-serialize', 'json-insert',
++'json-parse-string', and 'json-parse-buffer' are typically much faster
++than their Lisp counterparts from json.el.
+
++---
+** The configure option '--with-cairo' is no longer experimental.
+This builds Emacs with Cairo drawing, and supports built-in printing
- was invoked with the '-batch' option.
++when Emacs is built with GTK+. Some severe bugs in this build were
++fixed, and we can therefore offer this to users without caveats.
+
++++
+** Emacs now uses a "portable dumper" instead of unexec.
+This improves compatibility with memory allocation on modern systems,
+and in particular better supports the Address Space Layout
+Randomization (ASLR) feature, a security technique used by most modern
+operating systems.
+
+When built with the portable dumping support (which is the default),
+Emacs looks for the 'emacs.pdmp' file, generated during the build, in
+its data directory at startup, and loads the dumped state from there.
+The new command-line argument '--dump-file=FILE' allows to specify a
+non-default '.pdmp' file to load the state from; see the node "Initial
+Options" in the Emacs manual for more information.
+
+An Emacs started via a dump file can create a new dump file only if it
- deprecated.
++was invoked with the '-batch' option. (This is a temporary
++limitation; we plan on lifting it in a future release.)
+
+Although the portable dumper has been tested, it may have a bug on
+unusual platforms. If you require traditional unexec dumping you can
+use the configure-time option '--with-dumping=unexec'; however, please
+file a bug report describing the situation, as unexec dumping is
- +++
++deprecated, and we plan on removing it in some future release.
+
- +++
++---
+** The new configure option '--enable-checking=structs' attempts to
+check that the portable dumper code has been updated to match the last
+change to one of the data structures that it relies on.
+
- +++
++---
+** The configure options '--enable-checking=conslist' and
+'--enable-checking=xmallocoverrun' have been withdrawn. The former
+made Emacs irredeemably slow, and the latter made it crash. Neither
+option was useful with modern debugging tools such as AddressSanitizer.
+(See etc/DEBUG for the details of using the modern replacements of the
+removed configure options.)
+
- ** Emacs now builds with dynamic module support by default. Pass
- '--without-modules' to 'configure' to disable dynamic module support.
++---
++** Emacs no longer defaults to using ImageMagick to display images.
++This is due to security and stability concerns with ImageMagick. To
++override the default, use 'configure --with-imagemagick'.
++
++---
++** Several configure options now accept an option-argument 'ifavailable'.
++For example, './configure --with-xpm=ifavailable' now configures Emacs
++to attempt to use libxpm but to continue building even if libxpm is
++absent. The other affected options are '--with-gif', '--with-gnutls',
++'--with-jpeg', '--with-png', and '--with-tiff'.
++
++---
++** The 'etags' program now uses the C library's regular expression matcher.
++If it's possible, 'etags' will use the regexp matcher from the
++system's standard C library, otherwise it will be linked with a
++compatible regex substitute. This lets developers maintain Emacs's
++own regex code without having to also support other programs. The new
++configure option '--without-included-regex' forces 'etags' to use the C
++library's regex matcher even if the regex substitute ordinarily would
++be used to work around compatibility problems.
++
++---
++** Emacs has been ported to the '-fcheck-pointer-bounds' option of GCC.
++This causes Emacs to check bounds of some arrays addressed by its
++internal pointers, which can be helpful when debugging the Emacs
++interpreter or modules that it uses. If your platform supports it you
++can enable it when configuring, e.g., './configure CFLAGS="-g3 -O2
++-mmpx -fcheck-pointer-bounds"' on Intel MPX platforms.
++
++---
++** Emacs now normally uses a C pointer type instead of a C integer
++type to implement Lisp_Object, which is the fundamental machine word
++type internal to the Emacs Lisp interpreter. This change aims to
++catch typos and supports '-fcheck-pointer-bounds'. The 'configure'
++option '--enable-check-lisp-object-type' is therefore no longer as
++useful and so is no longer enabled by default in developer builds,
++to reduce differences between developer and production builds.
++
++---
+** The distribution tarball now has test cases; 'make check' runs them.
+This is intended mostly to help developers.
+
+---
+** Emacs now requires GTK 2.24 and GTK 3.10 for the GTK 2 and GTK 3
+builds respectively.
+
++---
+** New make target 'help' shows a summary of common make targets.
+
- *** emacsclient now supports an 'EMACS_SOCKET_NAME' environment variable.
++---
++** Emacs now builds with dynamic module support by default.
++Pass '--without-modules' to 'configure' to disable dynamic module
++support.
+
+\f
+* Startup Changes in Emacs 27.1
+
++++
+** Emacs now uses the XDG convention for init files.
+For example, it looks for init.el in "~/.config/emacs/init.el", and
+similarly for other init files.
+
+The XDG_CONFIG_HOME environment variable (which defaults to "~/.config")
+specifies the parent directory of these and other configuration files,
+and will override their traditional locations (the home directory,
+"~/.emacs.d", etc.).
+
+Emacs will still look for init files in their traditional locations if
+XDG_CONFIG_HOME does not exist, so invoking Emacs with
+XDG_CONFIG_HOME='/nowhere' might be useful if your new-location init
+files are scrambled, or if you want to force Emacs to ignore files
+under XDG_CONFIG_HOME for some other reason.
+
++++
+** Emacs can now be configured using an early init file.
+The file is called 'early-init.el', in 'user-emacs-directory'. It is
+loaded very early in the startup process: before graphical elements
+such as the tool bar are initialized, and before the package manager
+is initialized. The primary purpose is to allow customizing how the
+package system is initialized given that initialization now happens
+before loading the regular init file (see below).
+
+We recommend against putting any customizations in this file that
+don't need to be set up before initializing installed add-on packages,
+because the early init file is read too early into the startup
+process, and some important parts of the Emacs session, such as
+'window-system' and other GUI features, are not yet set up, which could
+make some customization fail to work.
+
++++
+** Installed packages are now activated *before* loading the init file.
+As a result of this change, it is no longer necessary to call
+'package-initialize' in your init file.
+
+Previously, a call to 'package-initialize' was automatically inserted
+into the init file when Emacs was started. This call can now safely
+be removed. Alternatively, if you want to ensure that your init file
+is still compatible with earlier versions of Emacs, change it to:
+
+(when (< emacs-major-version 27)
+ (package-initialize))
+
+However, if your init file changes the values of 'package-load-list'
+or 'package-user-dir', or sets 'package-enable-at-startup' to nil then
+it won't work right without some adjustment:
+- You can move that code to the early init file (see above), so those
+ settings apply before Emacs tries to activate the packages.
+- You can use the new 'package-quickstart' so activation of packages
+ does not need to pay attention to 'package-load-list' or
+ 'package-user-dir' any more.
+
+---
+** Emacs now notifies systemd when startup finishes or shutdown begins.
+Units that are ordered after 'emacs.service' will only be started
+after Emacs has finished initialization and is ready for use.
+(If your Emacs is installed in a non-standard location and you copied the
+emacs.service file to eg "~/.config/systemd/user/", you will need to copy
+the new version of the file again.)
+
+\f
+* Changes in Emacs 27.1
+
+++++
++** Emacs now supports resizing and rotating images without ImageMagick.
++All modern systems support this feature. (On GNU and Unix systems,
++Cairo drawing or the XRender extension to X11 is required for this to
++be available; the configure script will test for it and, if found,
++enable scaling.)
++
++The new function 'image-transforms-p' can be used to test whether any
++given frame supports these capabilities.
++
+++++
++** The Network Security Manager now allows more fine-grained control
++of what checks to run via the 'network-security-protocol-checks'
++user option.
++
+++++
++** TLS connections have their security tightened by default.
++Most of the checks for outdated, believed-to-be-weak TLS algorithms
++and ciphers are now switched on by default. (In addition, several new
++TLS weaknesses are now warned about.) By default, the NSM will
++flag connections using these weak algorithms and ask users whether to
++allow them. To get the old behavior back (where certificates are
++checked for validity, but no warnings about weak cryptography are
++issued), you can either set 'network-security-protocol-checks' to nil,
++or adjust the elements in that user option to only happen on the 'high'
++security level (assuming you use the 'medium' level).
++
++---
++** New user option 'nsm-trust-local-network'.
++Allows skipping Network Security Manager checks for hosts on your
++local subnet(s). It defaults to nil. Usually, there should be no
++need to set this non-nil, and doing that risks opening your local
++network connections to attacks. So be sure you know what you are
++doing before changing the value.
++
+++++
++** Native GnuTLS connections can now use client certificates.
++Previously, this support was only available when using the external
++'gnutls-cli' command. Call 'open-network-stream' with
++':client-certificate t' to trigger looking up of per-server
++certificates via 'auth-source'.
++
+++++
++** New user option 'network-stream-use-client-certificates'.
++When non-nil, 'open-network-stream' performs lookups of client
++certificates using 'auth-source' as if ':client-certificate t' were
++specified if there is no explicit ':client-certificate' parameter.
++Defaults to nil.
++
++++
+** 'next/previous-multiframe-window' have been renamed.
+The new names are as follows:
+
+ 'next-multiframe-window' -> 'next-window-any-frame'
+ 'previous-multiframe-window' -> 'previous-window-any-frame'
+
+The old function names are maintained as aliases for backward
+compatibility.
+
+** emacsclient
+
++++
- *** Emacs and emacsclient now default to "$XDG_RUNTIME_DIR/emacs"
- as the directory for client/server sockets, if Emacs is running
- on a platform or environment that sets the 'XDG_RUNTIME_DIR'
++*** emacsclient now supports the 'EMACS_SOCKET_NAME' environment variable.
+The command-line argument '--socket-name' overrides it.
+(The same behavior as for the pre-existing 'EMACS_SERVER_FILE' variable.)
+
++++
- +++
- ** The Network Security Manager now allows more fine-grained control
- of what checks to run via the 'network-security-protocol-checks'
- user option.
-
- +++
- ** TLS connections have their security tightened by default.
- Most of the checks for outdated, believed-to-be-weak TLS algorithms
- and ciphers are now switched on by default. (In addition, several new
- TLS weaknesses are now warned about.) By default, the NSM will
- flag connections using these weak algorithms and ask users whether to
- allow them. To get the old behavior back (where certificates are
- checked for validity, but no warnings about weak cryptography are
- issued), you can either set 'network-security-protocol-checks' to nil,
- or adjust the elements in that user option to only happen on the 'high'
- security level (assuming you use the 'medium' level).
-
- ---
- ** New user option 'nsm-trust-local-network'.
- Allows skipping Network Security Manager checks for hosts on your
- local subnet(s). It defaults to nil. Usually, there should be no
- need to set this non-nil, and doing that risks opening your local
- network connections to attacks. So be sure you know what you are
- doing before changing the value.
-
- +++
- ** Native GnuTLS connections can now use client certificates.
- Previously, this support was only available when using the external
- 'gnutls-cli' command. Call 'open-network-stream' with
- ':client-certificate t' to trigger looking up of per-server
- certificates via 'auth-source'.
-
- +++
- ** New user option 'network-stream-use-client-certificates'.
- When non-nil, 'open-network-stream' performs lookups of client
- certificates using 'auth-source' as if ':client-certificate t' were
- specified if there is no explicit ':client-certificate' parameter.
- Defaults to nil.
-
++*** Emacs and emacsclient now default to "$XDG_RUNTIME_DIR/emacs".
++This is used as the directory for client/server sockets, if Emacs is
++running on a platform or environment that sets the 'XDG_RUNTIME_DIR'
+environment variable to indicate where session sockets should go.
+To get the old, less-secure behavior, you can set the
+'EMACS_SOCKET_NAME' environment variable to an appropriate value.
+
+---
+*** When run by root, emacsclient no longer connects to non-root sockets.
+(Instead you can use Tramp methods to run root commands in a non-root Emacs.)
+
++++
+** New user option 'what-cursor-show-names'.
+When non-nil, 'what-cursor-position' will show the name of the character
+in addition to the decimal/hex/octal representation. Default nil.
+
++++
+** New function 'network-lookup-address-info'.
+This does IPv4 and/or IPv6 address lookups on hostnames.
+
++++
+** 'network-interface-list' can now return IPv4 and IPv6 addresses.
+IPv4 and IPv6 addresses are now returned by default if available,
+optionally including netmask/broadcast address information.
+
+---
+** Control of the threshold for using the 'distant-foreground' color.
+The threshold for color distance below which the 'distant-foreground'
+color of the face will be used instead of the foreground color can now
+be controlled via the new variable 'face-near-same-color-threshold'.
+The default value is 30000, as the previously hard-coded threshold.
+
++++
+** The function 'read-passwd' uses "*" as default character to hide passwords.
+
+** The function 'read-answer' now accepts not only single character
+answers, but also function keys like 'F1', character events such as
+'C-M-h', and control characters like 'C-h'.
+
+** Lexical binding is now used when evaluating interactive Elisp forms.
+More specifically, lexical-binding is now used for 'M-:', '--eval', as
+well as in the "*scratch*" and "*ielm*" buffers.
+
+---
+** The new user option 'tooltip-resize-echo-area' avoids truncating
+tooltip text on GUI frames when tooltips are displayed in the echo
+area. Instead, it resizes the echo area as needed to accommodate the
+full tool-tip text.
+
+---
+** Show mode line tooltips only if the corresponding action applies.
+Customize the user option 'mode-line-default-help-echo' to restore the
+old behavior where the tooltip text is also shown when the
+corresponding action does not apply.
+
++++
+** New hook 'server-after-make-frame-hook'.
+This hook is a convenient place to perform initializations in daemon
+mode which require GUI features to be available. One example is
+restoration of the previous session using the desktop.el package: put
+the call to 'desktop-read' in this hook, if you want the GUI settings
+to be restored, or if desktop.el needs to interact with you during
+restoration of the session.
+
++++
+** The functions 'set-frame-height' and 'set-frame-width' are now
+commands, and will set the currently selected frame to the height/
+width specified by the numeric prefix.
+
++++
+** New function 'logcount' calculates an integer's Hamming weight.
+
++++
+** New function 'libxml-available-p'.
+This function returns non-nil if libxml support is both compiled in
+and available at run time. Lisp programs should use this function to
+detect built-in libxml support, instead of testing for that
+indirectly, e.g., by checking that functions like
+'libxml-parse-html-region' return nil.
+
++++
+** 'libxml-parse-xml-region' and 'libxml-parse-html-region' take
+a parameter that's called DISCARD-COMMENTS, but it really only
+discards the top-level comment. Therefore this parameter is now
+obsolete, and the new utility function 'xml-remove-comments' can be
+used to remove comments before calling the libxml functions to parse
+the data.
+
++++
+** A new DOM (the XML/HTML document structure returned by functions
+such as 'libxml-parse-html-region') traversal function has been added:
+'dom-search', which takes a DOM and a predicate and returns all nodes
+that match.
+
- ** In Japanese environments that do not specify encodings and are not
++++
+** New function 'fill-polish-nobreak-p', to be used in 'fill-nobreak-predicate'.
+It blocks line breaking after a one-letter word, also in the case when
+this word is preceded by a non-space, but non-alphanumeric character.
+
++++
+** The limit on repetitions in regexps has been raised to 2^16-1.
+It was previously limited to 2^15-1. For example, the following
+regular expression was previously invalid, but is now accepted:
+
+ x\{32768\}
+
+---
+** The German prefix and postfix input methods now support Capital sharp S.
+
+---
+** New input methods 'hawaiian-postfix' and 'hawaiian-prefix'.
+
+---
+** New input methods 'georgian-qwerty' and 'georgian-nuskhuri'.
+
+---
+** New input methods for several variants of the Sami language.
+The Sami input methods include: 'norwegian-sami-prefix',
+'bergsland-hasselbrink-sami-prefix', 'southern-sami-prefix',
+'ume-sami-prefix', 'northern-sami-prefix', 'inari-sami-prefix',
+'skolt-sami-prefix', and 'kildin-sami-prefix'.
+
++++
- ---
- ** More commands support noncontiguous rectangular regions, namely
- 'upcase-dwim', 'downcase-dwim', 'capitalize-dwim', 'capitalize-region',
- 'upcase-initials-region', 'replace-string', 'replace-regexp', and
- 'delimit-columns-region'.
-
- +++
- ** When asked to visit a large file, Emacs now offers visiting it literally.
- Previously, Emacs would only ask for confirmation before visiting
- large files. Now it also offers a third alternative: to visit the
- file literally, as in 'find-file-literally', which speeds up
- navigation and editing of large files.
-
++** Japanese environments use UTF-8 by default.
++In Japanese environments that do not specify encodings and are not
+based on MS-Windows, the default encoding is now utf-8 instead of
+japanese-iso-8bit.
+
++++
+** New function 'exec-path'.
+This function by default returns the value of the corresponding
+user option, but can optionally return the equivalent of 'exec-path'
+from a remote host.
+
++++
+** The function 'executable-find' supports an optional argument REMOTE.
+This triggers to search the program on the remote host as indicated by
+'default-directory'.
+
++++
+** New user option 'auto-save-no-message'.
+When set to t, no message will be shown when auto-saving (default
+value: nil).
+
+---
+** The value of 'make-cursor-line-fully-visible' can now be a function.
+In addition to nil or non-nil, the value can now be a predicate
+function. Follow mode uses this to control scrolling of its windows
+when the last screen line in a window is not fully visible.
+
++++
+** New variable 'emacs-repository-branch'.
+It reports the git branch from which Emacs was built.
+
++++
+** New user option 'switch-to-buffer-obey-display-actions'.
+When non-nil, 'switch-to-buffer' uses 'pop-to-buffer-same-window' that
+respects display actions specified by 'display-buffer-alist' and
+'display-buffer-overriding-action'.
+
++++
+** The user option 'switch-to-visible-buffer' is now obsolete.
+Customize 'switch-to-prev-buffer-skip' instead.
+
++++
+** New user option 'switch-to-prev-buffer-skip'.
+This user option allows to specify the set of buffers that may be
+shown by 'switch-to-prev-buffer' and 'switch-to-next-buffer' more
+stringently than the now obsolete 'switch-to-visible-buffer'.
+
+** New 'flex' completion style
+An implementation of popular "flex/fuzzy/scatter" completion which
+matches strings where the pattern appears as a subsequence. Put
+simply, makes "foo" complete to both "barfoo" and "frodo". Add 'flex'
+to 'completion-styles' or 'completion-category-overrides' to use it.
+
+** The 'completion-common-part' face is now visible by default.
+
++++
+** New face attribute ':extend' to control face extension at EOL.
+The new face attribute ':extend' controls whether to use the face for
+displaying the empty space beyond end of line (EOL) till the edge of
+the window. By default, this attribute is non-nil only for a small
+number of faces, notably, 'region'; any other face that crosses end of
+line will not affect the display of the empty space at EOL. This is
+to make Emacs behave more like other GUI applications with respect to
+displaying faces that cross line boundaries.
+
+This attribute behaves specially when theme definitions are applied:
+if the theme doesn't specify an explicit value of this attribute for a
+face, the value from the original face definition is inherited.
+Consequently, a theme generally shouldn't specify this attribute
+unless it has a good reason to do so.
+
+** Connection-local variables
+
++++
+*** Connection-local variables are applied by default like file-local
+and directory-local variables.
+
++++
+*** The macro 'with-connection-local-variables' has been renamed from
+'with-connection-local-profiles'. No argument PROFILES needed any longer.
+
+---
+** New user option 'next-error-verbose' controls when 'next-error'
+outputs a message about the error locus.
+
+---
+** New user option 'grep-search-path' defines the directories searched for
+grep hits (this used to be controlled by 'compilation-search-path').
+
+---
+** New user option 'emacs-lisp-compilation-search-path' defines the
+directories searched for byte-compiler error messages (this used to
+be controlled by 'compilation-search-path').
+
++---
+** Multicolor fonts such as "Noto Color Emoji" can be displayed on
+Emacs configured with Cairo drawing and linked with cairo >= 1.16.0.
+
++++
+** Emacs now optionally displays a fill column indicator.
+
+This is similar to what 'fill-column-indicator' package provides, but
+much faster and compatible with 'show-trailing-whitespace'.
+
+Customize the buffer-local user options 'display-fill-column-indicator'
+and 'display-fill-column-indicator-character' to activate the
+indicator.
+
+The indicator is not displayed at all in minibuffer windows and
+in tooltips, as it is not useful there.
+
+There are 2 new buffer local variables and 1 face to customize this
+mode they are described in the manual "(emacs) Display".
+
++++
+** 'progress-reporter-update' accepts a suffix string to display.
+
+---
+** New user option 'xref-file-name-display' controls the display of
+file names in xref buffers.
+
+** New user option 'byte-count-to-string-function'.
+It is used for displaying file sizes and disk space in some cases.
+
++++
+** Emacs now interprets RGB triplets like HTML, SVG, and CSS do.
+
+The X convention previously used differed slightly, particularly for
+RGB triplets with a single hexadecimal digit per component.
+
+---
+** The toolbar now shows the equivalent key binding in its tooltips.
+
+---
+** The File menu-bar menu was re-arranged: Print menu items moved to
+submenu, and also added the new entries for tabs.
+
+---
+** 'scroll-lock-mode' is now bound to the 'Scroll_Lock' key globally.
+Note that this key binding will not work on MS-Windows systems if
+'w32-scroll-lock-modifier' is non-nil.
+
+---
+** 'global-set-key', called interactively, now no longer downcases a
+key binding with an upper case letter - if you can type it, you can
+bind it.
+
++++
+** 'read-from-minibuffer' now works with buffer-local history variables.
+The HIST argument of 'read-from-minibuffer' now works correctly with
+buffer-local variables. This means that different buffers can have
+their own separated input history list if desired.
+
+** 'backup-by-copying-when-privileged-mismatch' applies to file gid, too.
+In addition to checking the file owner uid, Emacs also checks that the
+group gid is not greater than 'backup-by-copying-when-privileged-mismatch';
+if so, 'backup-by-copying-when-mismatch' will be forced on.
+
+\f
+* Editing Changes in Emacs 27.1
+
+++++
++** When asked to visit a large file, Emacs now offers visiting it literally.
++Previously, Emacs would only ask for confirmation before visiting
++large files. Now it also offers a third alternative: to visit the
++file literally, as in 'find-file-literally', which speeds up
++navigation and editing of large files.
++
++++
+** 'zap-to-char' now uses history of characters you used to zap to.
+'zap-to-char' uses the new 'read-char-from-minibuffer' function to allow
+navigating through the history of characters that have been input.
+This is mostly useful for characters that have complex input methods
+where inputting the character again may involve many keystrokes.
+
++++
+** 'save-some-buffers' now has a new action in the prompt: 'C-f' will
+exit the command and switch to the buffer currently being asked about.
+
++---
++** More commands support noncontiguous rectangular regions, namely
++'upcase-dwim', 'downcase-dwim', 'capitalize-dwim', 'capitalize-region',
++'upcase-initials-region', 'replace-string', 'replace-regexp', and
++'delimit-columns-region'.
++
++++
+** The new 'amalgamating-undo-limit' variable can be used to control
+how many changes should be amalgamated when using the 'undo' command.
+
+---
+** The 'newline-and-indent' command (commonly bound to 'RET' in many
+modes) now takes an optional numeric argument to specify how many
+times is should insert newlines (and indent).
+
++++
+** New command 'make-empty-file'.
+
+---
+** New variable 'x-wait-for-event-timeout'.
+This controls how long Emacs will wait for updates to the graphical
+state to take effect (making a frame visible, for example).
+
++++
+** New user option 'electric-quote-replace-double'.
+This option controls whether '"' is replaced in 'electric-quote-mode',
+in addition to other quote characters. If non-nil, ASCII double-quote
+characters that quote text "like this" are replaced by double
+typographic quotes, “like this”, in text modes, and in comments in
+non-text modes.
+
+---
+** New user option 'flyspell-case-fold-duplications'.
+This option controls whether Flyspell mode considers consecutive words
+to be duplicates if they are not in the same case. If non-nil, the
+default, words are considered to be duplicates even if their letters'
+case does not match.
+
+---
+** 'write-abbrev-file' now includes special properties.
+'write-abbrev-file' now writes special properties like ':case-fixed'
+for abbrevs that have them.
+
++++
+** 'write-abbrev-file' skips empty tables.
+'write-abbrev-file' now skips inserting a 'define-abbrev-table' form for
+tables which do not have any non-system abbrevs to save.
+
++++
+** The new functions and commands 'text-property-search-forward' and
+'text-property-search-backward' have been added. These provide an
+interface that's more like functions like 'search-forward'.
+
- *** 'windmove-create-window' when non-nil makes a new window on moving off
- the edge of the frame.
+---
+** 'add-dir-local-variable' now uses dotted pair notation syntax to
+write alists of variables to ".dir-locals.el". This is the same
+syntax that you can see in the example of a ".dir-locals.el" file in
+the node "(emacs) Directory Variables" of the user manual.
+
++++
+** Network connections using 'local' can now use IPv6.
+'make-network-process' now uses the correct loopback address when
+asked to use ':host 'local' and ':family 'ipv6'.
+
++++
+** The new function 'replace-region-contents' replaces the current
+region using a given replacement-function in a non-destructive manner
+(in terms of 'replace-buffer-contents').
+
++++
+** The command 'replace-buffer-contents' now has two optional
+arguments mitigating performance issues when operating on huge
+buffers.
+
++++
+** Dragging 'C-M-mouse-1' now marks rectangular regions.
+
++++
+** The command 'delete-indentation' now operates on the active region.
+If the region is active, the command joins all the lines in the
+region. When there's no active region, the command works on the
+current and the previous or the next line, as before.
+
+++++
++** You can now change the font size with the mouse wheel.
++Scroling the mouse wheel with the Ctrl key pressed will now act the
++same as the 'C-x C-+' and 'C-x C--' commands.
++
+\f
+* Changes in Specialized Modes and Packages in Emacs 27.1
+
+---
+** New HTML mode skeleton 'html-id-anchor'.
+This new command (which inserts an <a id="foo">_</a> skeleton) is
+bound to 'C-c C-c #'.
+
++++
+** New command 'font-lock-refontify'.
+This is an interactive convenience function to be used when developing
+font locking for a mode. It recomputes the font locking data and then
+re-fontifies the buffer.
+
+---
+** Font Lock is smarter about fontifying unterminated strings and comments.
+When you type a quote that starts a string, or a comment delimiter
+that starts a comment, font-lock will not immediately refontify the
+following characters in 'font-lock-string-face' or
+'font-lock-comment-face'. Instead, it will delay the fontification
+beyond the current line to give you a chance to close the string or
+comment. This is controlled by the new user option
+'jit-lock-antiblink-grace', which specifies the delay in seconds. The
+default is 2 seconds; set to nil to get back the old behavior.
+
+---
+** The 'C' command in 'tar-mode' will now preserve the timestamp of
+the extracted file if the new user option 'tar-copy-preserve-time' is
+non-nil.
+
+---
+** 'autoconf-mode' is now used instead of 'm4-mode' for the
+acinclude.m4/aclocal.m4/acsite.m4 files.
+
+---
+** On GNU/Linux, 'M-x battery' will now list all batteries, no matter
+what they're named, and the 'battery-linux-sysfs-regexp' variable has
+been removed.
+
+** The 'list-processes' command now includes port numbers in the
+network connection information (in addition to the host name).
+
+** The 'cl' package is now officially deprecated in favor of 'cl-lib'.
+
+---
+** desktop
+*** When called interactively with a prefix arg 'C-u', 'desktop-read'
+now prompts the user for the directory containing the desktop file.
+
++++
+** display-line-numbers-mode
+
+*** New faces 'line-number-major-tick' and 'line-number-minor-tick',
+and user options 'display-line-numbers-major-tick' and
+'display-line-numbers-minor-tick' can be used to highlight the line
+numbers of lines multiple of certain numbers.
+
+*** New variable 'display-line-numbers-offset', when non-zero, adds
+an offset to absolute line numbers.
+
++++
+** winner
+*** A new user option, 'winner-boring-buffers-regexp', has been added.
+
+** table
+** 'table-generate-source' and friends now support outputting wiki and
+mediawiki format tables.
+
+---
+** telnet-mode
+*** Reverting a buffer in 'telnet-mode' will restart a closed connection.
+
+** goto-addr
+*** A way to more conveniently specify what URI address schemes that
+should be ignored have been added via the
+'goto-address-uri-schemes-ignored' variable.
+
++++
+** tex-mode
+*** 'latex-noindent-commands' controls indentation of certain commands.
+You can use this new user option to control indentation of arguments of
+\emph, \footnote, and similar commands.
+
+** byte compiler
+*** 'byte-compile-dynamic' is now obsolete.
+This is because on the one hand it suffers from misbehavior in corner
+cases that have plagued it for years, and on the other experiments indicated
+that it doesn't bring any measurable benefit.
+
+---
+*** The 'g' keystroke in *Compile-Log* buffers has been bound to a new
+command that will recompile the file previously compiled with 'M-x
+byte-compile-file' and the like.
+
+** compile.el
+---
+*** In 'compilation-error-regexp-alist', 'line' (and 'end-line') can
+be functions.
++++
+*** 'compilation-context-lines' can now take the value t; this is like
+nil, but instead of scrolling the current line to the top of the
+screen when there is no left fringe, it inserts a visible arrow before
+column zero.
+---
+*** The new 'compilation-transform-file-match-alist' user option can
+be used to transform file name matches compilation output, and remove
+known false positives being recognized as warnings/errors.
+
+** cl-lib.el
++++
+*** 'cl-defstruct' has a new ':noinline' argument to prevent inlining
+its functions.
+
++++
+*** 'cl-defstruct' slots accept a ':documentation' property.
+
+---
+*** 'cl-values-list' will now signal an error if its argument isn't a list.
+
+** doc-view.el
+*** New commands 'doc-view-presentation' and 'doc-view-fit-window-to-page'.
+*** Added support for password-protected PDF files
+
+*** A new user option 'doc-view-pdftotext-program-args' has been added
+to allow controlling how the conversion to text is done.
+
+** Ido
+*** New user option 'ido-big-directories' to mark directories whose
+names match certain regular expressions as big. Ido won't attempt to
+list the contents of such directories when completing file names.
+
+** Minibuffer
+
++++
+*** A new user option, 'minibuffer-beginning-of-buffer-movement', has
+been introduced to allow controlling how the 'M-<' command works in
+the minibuffer. If non-nil, point will move to the end of the prompt
+(if point is after the end of the prompt).
+
++++
+*** When the minibuffer is active, echo-area messages are displayed at
+the end of the minibuffer instead of hiding the minibuffer by the echo
+area display. The new user option 'minibuffer-message-clear-timeout'
+controls how messages displayed in this situation are removed from the
+minibuffer.
+
+---
+*** Minibuffer now uses 'minibuffer-message' to display error messages
+at the end of the active minibuffer.
+
++++
+*** 'y-or-n-p' now uses the minibuffer to read 'y' or 'n' answer.
+
++---
+*** Some commands that previously used 'read-char-choice' now read
+a character using the minibuffer by 'read-char-from-minibuffer'.
+
+** map.el
+*** Now also understands plists.
+*** Now defined via generic functions that can be extended via 'cl-defmethod'.
+*** Deprecate the 'map-put' macro in favor of a new 'map-put!' function.
+*** 'map-contains-key' now returns a boolean rather than the key.
+*** Deprecate the 'testfn' args of 'map-elt' and 'map-contains-key'.
+*** New generic function 'map-insert'.
+
++++
+*** The 'type' arg can be a list '(hash-table :key1 VAL1 :key2 VAL2 ...)'.
+
+** seq.el
+New convenience functions 'seq-first' and 'seq-rest' give easy access
+to respectively the first and all but the first elements of sequences.
+
+The new predicate function 'seq-contains-p' should be used instead of
+the now obsolete 'seq-contains'.
+
+---
+** Follow mode
+In the current follow group of windows, "ghost" cursors are no longer
+displayed in the non-selected follow windows. To get the old behavior
+back, customize 'follow-hide-ghost-cursors' to nil.
+
++++
+** New variable 'warning-fill-column' for 'display-warning'.
+
+** Windmove
+
- *** Windmove code no longer used is now obsolete. That includes the
- user option 'windmove-window-distance-delta' and the functions
- 'windmove-coord-add', 'windmove-constrain-to-range',
++---
++*** 'windmove-create-window' when non-nil makes a new window.
++This happens upon moving off the edge of the frame.
+
++---
+*** Windmove supports directional window display and selection.
+The new command 'windmove-display-default-keybindings' binds default
+keys with provided modifiers (by default, Shift-Meta) to the commands
+that display the next buffer in the window at the specified direction.
+This is like 'windmove-default-keybindings' that binds keys to commands
+that select the window in the specified direction, but additionally it
+displays the buffer from the next command in that window. For example,
+'S-M-right C-h i' displays the "*Info*" buffer in the right window,
+creating the window if necessary. A special key can be customized to
+display the buffer in the same window, for example, 'S-M-0 C-h e'
+displays the "*Messages*" buffer in the same window. 'S-M-t C-h C-n'
+displays NEWS in a new tab.
+
++---
+*** Windmove also supports directional window deletion.
+The new command 'windmove-delete-default-keybindings' binds default
+keys with provided prefix (by default, 'C-x') and modifiers (by default,
+'Shift') to the commands that delete the window in the specified
+direction. For example, 'C-x S-down' deletes the window below.
+With a prefix arg 'C-u', also kills the buffer in that window.
+With 'M-0', deletes the selected window and selects the window
+that was in the specified direction.
+
++---
+*** New command 'windmove-swap-states-in-direction' binds default keys
+to the commands that swap the states of the selected window with the
+window in the specified direction.
+
- *** New command and keystroke 'dired-number-of-marked-files' bound to
- '* N'.
++---
++*** Windmove code no longer used is now obsolete.
++That includes the user option 'windmove-window-distance-delta' and the
++functions 'windmove-coord-add', 'windmove-constrain-to-range',
+'windmove-constrain-around-range', 'windmove-frame-edges',
+'windmove-constrain-loc-for-movement', 'windmove-wrap-loc-for-movement',
+'windmove-reference-loc' and 'windmove-other-window-loc'.
+
+** Octave mode
+The mode is automatically enabled in files that start with the
+'function' keyword.
+
+** project.el
+
+*** New commands 'project-search' and 'project-query-replace-regexp'.
+
+*** New user option 'project-read-file-name-function'.
+
+** Etags
+
++++
+*** 'next-file' is now an obsolete alias of 'tags-next-file'.
+
++---
+*** 'tags-loop-revert-buffers' is an obsolete alias of
+'fileloop-revert-buffers'.
+
+++++
+*** The 'tags-loop-continue' function along with the
+'tags-loop-operate' and 'tags-loop-scan' variables are now obsolete;
+use the new 'fileloop-initialize' and 'fileloop-continue' functions
+instead.
+
++++
+*** etags is now able to read Zstandard-compressed files.
+
+** bibtex
+
+---
+*** New commands 'bibtex-next-entry' and 'bibtex-previous-entry'.
+In 'bibtex-mode-map', 'forward-paragraph' and 'backward-paragraph' are
+remapped to these, respectively.
+
+** Dired
+
+---
+*** On systems that support suid/guid files, Dired now fontifies the
+permissions of such files with a special face 'dired-set-id'.
+
++++
+*** New command 'dired-create-empty-file'.
+
++++
- *** New sorting options for the user option 'find-ls-option'.
-
++*** New command 'dired-number-of-marked-files'.
++It is by default bound to '* N'.
+
++---
+*** The marking commands now report how many files were marked by the
+command itself, not how many files are marked in total.
+
+---
+*** A new face, 'dired-special', is used to highlight sockets, named
+pipes, block devices and character devices.
+
++++
+*** The new user option 'dired-create-destination-dirs' controls whether
+'dired-do-copy' and 'dired-rename-file' should create non-existent
+directories in the destination.
+
++++
+*** 'dired-dwim-target' can be customized to prefer either the next window,
+or one of the most recently visited windows with a Dired buffer.
+
+++++
+*** When the new user option 'dired-vc-rename-file' is non-nil,
+Dired performs file renaming using underlying version control system.
+
++---
++*** Zstandard compression is now supported for 'dired-do-compress' and
++'dired-do-compress-to'.
++
+** Find-Dired
+
++---
+*** New user option 'find-dired-refine-function'.
+The default value is 'find-dired-sort-by-filename'.
+
- *** Zstandard compression is now supported for 'dired-do-compress' and
- 'dired-do-compress-to'.
+---
- *** 'vc-git-stash' has now been bound to the 'C' keystroke in the
- stash headers.
++*** New sorting options for the user option 'find-ls-option'.
+
+** Change Logs and VC
+
+---
+*** New user option 'vc-tor'.
+When non-nil, this user option causes the VC commands to communicate
+with the repository via Tor's proxy, using the 'torsocks' wrapper
+script. The default is nil.
+
++++
+*** New command 'log-edit-generate-changelog-from-diff', bound to 'C-c C-w'.
+This generates ChangeLog entries from the VC fileset diff.
+
++---
+*** 'vc-dir' now shows a button allowing you to hide the stash list.
+Controlled by user option 'vc-git-show-stash'. Default t means show
+the entire list as before. An integer value limits the list length
+(but still allows you to show the entire list via the button).
+
+++++
+*** Recording ChangeLog entries doesn't require an actual file.
+If a ChangeLog file doesn't exist, and if the new user option
+'add-log-dont-create-changelog-file' is non-nil (which is the
+default), commands such as 'C-x 4 a' will add log entries to a
+suitable named temporary buffer. (An existing ChangeLog file will
+still be used if it exists.) Set the user option to nil to get the
+previous behavior of always creating a buffer that visits a ChangeLog
+file.
+
++---
+*** New user option 'vc-find-revision-no-save'.
+With non-nil, 'vc-find-revision' doesn't write the created buffer to file.
+
+---
+*** 'vc-dir-ignore' now takes a prefix argument to ignore all marked files.
+
++---
+*** New user option 'vc-git-grep-template'.
+This new user option allows customizing the default arguments passed to
+'git-grep' when 'vc-git-grep' is used.
+
++---
+*** Command 'vc-git-stash' now respects marks in the "*vc-dir*" buffer.
+When some files are marked, only those are stashed.
+When no files are marked, all modified files are stashed, as before.
+
- *** New user option 'vc-hg-revert-switches' specifies switches to pass
- to Hg revert.
++---
++*** 'vc-git-stash' is now bound to 'C' in the stash headers.
+
++--
+*** Some stash keybindings are now available in the stash button.
+'vc-git-stash' and 'vc-git-stash-snapshot' can now be run using 'C'
+and 'S' respectively, including when there are no stashes.
+
++---
+*** The new hook 'vc-retrieve-tag-hook' runs after retrieving a tag.
+
+---
+*** 'vc-hg' now invokes 'smerge-mode' when visiting files.
+Code that attempted to invoke 'smerge-mode' when visiting an Hg file
+with conflicts existed in earlier versions of Emacs, but incorrectly
+never detected a conflict due to invalid assumptions about cached
+values.
+
++++
+*** The Hg (Mercurial) back-end now supports 'vc-region-history'.
+The 'C-x v h' command now works in buffers that visit files controlled
+by Hg.
+
++++
+*** The Hg (Mercurial) back-end now prompts for revision to merge when
+you invoke 'C-x v m' ('vc-merge').
+
+---
+*** The Hg (Mercurial) back-end now use tags, branches and bookmarks
+instead of revision numbers as completion candidates when it prompts
+for a revision.
+
++++
+*** 'C-u C-x v D' ('vc-root-version-diff') prompts for two revisions
+and compares their entire trees.
+
- *** A new user option, 'browse-url-secondary-browser-function', has been added.
++*** New user option 'vc-hg-revert-switches'.
++It specifies switches to pass to Hg's 'revert' command.
+
+*** 'C-x v M D' ('vc-diff-mergebase') and 'C-x v M L' ('vc-log-mergebase')
+print diffs and logs between the merge base (common ancestor) of two
+given revisions.
+
++++
+*** The new 'd' command ('vc-dir-clean-files') in 'vc-dir-mode'
+buffers will delete the marked files (or if no files are marked, the
+file under point). This command does not notify the VC backend, and
+is mostly useful for unregistered files.
+
+++++
+*** New command 'vc-log-search' asks for a pattern, searches it
+in the revision log, and displays matched log entries in the
+log buffer. For example, 'M-x vc-log-search RET bug#36644 RET'
+displays all entries whose log messages match the bug number.
+With a prefix argument asks for a command, so for example,
+'C-u M-x vc-log-search RET git log -1 f302475 RET' will display
+just one log entry found by its revision number.
+
++++
+*** It is now possible to display a specific revision given by its ID.
+If you invoke 'C-x v L' ('vc-print-root-log') with a numeric argument
+of 1, as in 'C-1 C-x v L' or 'C-u 1 C-x v L', it asks for a revision
+ID, and shows its log entry together with the diffs introduced by the
+revision's commit. (For some less capable VCSes, only the log entry
+is shown.)
+
++---
+*** 'C-x v =' can now mimic Magit's diff format.
+Set the new user option 'diff-font-lock-prettify' to t for that, see
+below under "Diff mode".
+
+---
+*** The 'diff' function arguments OLD and NEW may each be a buffer
+rather than a file, in non-interactive calls. This change was made in
+Emacs 24.1, but wasn't documented until now.
+
++++
+*** New command 'diff-buffers' interactively diffs two buffers.
+
+** Diff mode
++++
+*** Hunks are now automatically refined by font-lock.
+To disable refinement, set the new user option 'diff-refine' to nil.
+To get back the old behavior where hunks are refined as you navigate
+through a diff, set 'diff-refine' to the symbol 'navigate'.
+
++++
+*** 'diff-auto-refine-mode' is deprecated in favor of 'diff-refine'.
+It is no longer enabled by default and binding it no longer has any
+effect.
+
++++
+*** Better syntax highlighting of Diff hunks.
+Fragments of source in Diff hunks are now by default highlighted
+according to the appropriate major mode. Customize the new user
+option 'diff-font-lock-syntax' to nil to disable this.
+
++---
+*** File headers can be shortened, mimicking Magit's diff format.
+To enable it, set the new user option 'diff-font-lock-prettify' to t.
+On GUI frames, this option also displays the insertion and deletion
+indicators on the left fringe.
+
++++
+*** Prefix arg of 'diff-goto-source' means jump to the old revision
+of the file under version control if point is on an old changed line,
+or to the new revision of the file otherwise.
+
+** Texinfo
+
++++
+*** New function for inserting '@pxref', '@xref', or '@ref' commands.
+The function 'texinfo-insert-dwim-@ref', bound to 'C-c C-c r' by
+default, inserts one of three types of references based on the text
+surrounding point, namely '@pxref' near a parenthesis, '@xref' at the
+start of a sentence or at '(point-min)', else '@ref'.
+
+** Browse-url
+
++---
+*** The function 'browse-url-emacs' can now visit a URL in selected window.
+It now treats the optional 2nd argument to mean that the URL should be
+shown in the currently selected window.
+
++---
+*** A new function, 'browse-url-add-buttons' can be used to add clickable
+links to most ordinary special-mode buffers that display text that
+have URLs embedded. 'browse-url-button-regexp' controls what's
+considered a button.
+
- *** Change of 'package-check-signature' for packages with multiple sigs
++---
++*** New user option 'browse-url-secondary-browser-function'.
++It can be set to a function that invokes an alternative browser.
+
+** Comint
+
++++
+*** 'send-invisible' is now an obsolete alias for 'comint-send-invisible'.
+Also, 'shell-strip-ctrl-m' is declared obsolete.
+
++++
+*** 'C-c .' ('comint-insert-previous-argument') no longer interprets '&'.
+This feature caused problems when '&&' was present in the previous
+command. Since this command emulates 'M-.' in Bash and zsh, neither
+of which treats '&' specially, the feature was removed for
+compatibility with these shells.
+
++++
+*** 'comint-insert-previous-argument' can now count arguments from the end.
+By default, invoking 'C-c .' with a numeric argument N would copy the
+Nth argument, counting from the first one. But if the new user option
+'comint-insert-previous-argument-from-end' is non-nil, it will copy
+the Nth argument counting from the last one. Thus 'C-c .' can now
+better emulate 'M-.' in both Bash and zsh, since the former counts
+from the beginning of the arguments, while the latter counts from the
+end.
+
++++
+*** 'comint-run' can now accept a list of switches to pass to the program.
+'C-u M-x comint-run' will prompt for the switches interactively.
+
+++++
+*** Abnormal hook 'comint-password-function' has been added.
+This hook permits a derived mode to supply a password for the
+underlying command interpreter without prompting the user. For
+example, in 'sql-mode', the password for connecting to the database may
+be stored in the connection wallet and may be passed on the command
+line to start the SQL interpreter. This is a potential security flaw
+that could expose user's database passwords on the command line
+through the use of a process list (Bug#8427). With this hook, it is
+possible to not pass the password on the command line and wait for the
+program to prompt for the password. When it does so, the password can
+be supplied to the SQL interpreter without involving the user just as
+if it had been supplied on the command line.
+
+** SQL
+
++---
+*** SQL Indent Minor Mode
+SQL Mode now supports the ELPA 'sql-indent' package for assisting
+sophisticated SQL indenting rules. Note, however, that SQL is not
+like other programming languages like C, Java, or Python where code is
+sparse and rules for formatting are fairly well established. Instead
+SQL is more like COBOL (from which it came) and code tends to be very
+dense and line ending decisions driven by syntax and line length
+considerations to make readable code. Experienced SQL developers may
+prefer to rely upon existing Emacs facilities for formatting code but
+the 'sql-indent' package provides facilities to aid more casual SQL
+developers layout queries and complex expressions.
+
++---
+**** 'sql-use-indent-support' (default t) enables SQL indention support.
+The 'sql-indent' package from ELPA must be installed to get the
+indentation support in 'sql-mode' and 'sql-interactive-mode'.
+
++---
+**** 'sql-mode-hook' and 'sql-interactive-mode-hook' changed.
+Both hook variables have had 'sql-indent-enable' added to their
+default values. If you have existing customizations to these
+variables, you should make sure that the new default entry is
+included.
+
++---
+*** Connection Wallet
+Database passwords can now by stored in NETRC or JSON data files that
+may optionally be encrypted. When establishing an interactive session
+with the database via 'sql-connect' or a product specific function,
+like 'sql-mysql' or 'my-postgres', the password wallet will be
+searched for the password. The 'sql-product', 'sql-server',
+'sql-database', and the 'sql-username' will be used to identify the
+appropriate authorization. This eliminates the discouraged practice of
+embedding database passwords in your Emacs initialization.
+
+See the 'auth-source' module for complete documentation on the file
+formats. By default, the wallet file is expected to be in the
+'user-emacs-directory', named 'sql-wallet' or '.sql-wallet', with
+'.json' (JSON) or no (NETRC) suffix. Both file formats can optionally
+be encrypted with GPG by adding an additional '.gpg' suffix.
+
+** Term
+
+---
+*** 'term-read-noecho' is now obsolete, use 'read-passwd' instead.
+
++++
+*** 'serial-term' now takes an optional parameter to leave the
+emulator in line mode.
+
+** Flymake
+
++++
+*** The variable 'flymake-diagnostic-types-alist' is obsolete.
+You should instead set properties on known diagnostic symbols, like
+':error' and ':warning', as demonstrated in the Flymake manual.
+
+++++
+*** New user option 'flymake-start-on-save-buffer'.
+Control whether Flymake starts checking the buffer on save.
+
++---
+*** Flymake and backend functions may exchange hints about buffer changes.
+This enables more efficient backends. See the docstring of
+'flymake-diagnostic-functions' or the Flymake manual for details.
+
++++
+*** 'flymake-start-syntax-check-on-newline' is now obsolete,
+use 'post-self-insert-hook' to check on newline.
+
+** Ruby
+
++---
+*** The Rubocop Flymake diagnostic function will only run Lint cops if
+it can't find the config file.
+
++---
+*** Rubocop is called with 'bundle exec' if Gemfile mentions it.
+
++---
+*** New command 'ruby-find-library-file' bound to 'C-c C-f'.
+
+** Package
+
++---
+*** Warn if "footer line" is missing, but still install package.
+package.el used to refuse to install a package without the so-called
+"footer line", which appears at the very end of the file:
+
+;;; FILENAME ends here
+
+package.el will now install packages without this line, but it will
+issue a warning. To avoid this warning, packages should keep the
+"footer line".
+
+Note that versions of Emacs older than 27.1 will not only refuse to
+install packages without such a line -- they will be unable to parse
+package data. It is therefore recommended to keep this line.
+
- *** New user option 'gnus-use-atomic-windows' makes Gnus window layouts
- atomic. See the "Atomic Windows" section of the Elisp manual for
- details.
+++++
++*** Change of 'package-check-signature' for packages with multiple sigs.
+In previous Emacsen, 't' checked that all signatures are valid.
+Now 't' only checks that at least one signature is valid and the new 'all'
+value needs to be used if you want to enforce that all signatures
+are valid. This only affects packages with multiple signatures.
+
++++
+*** The meaning of 'allow-unsigned' in 'package-check-signature' has
+changed slightly: If a usable OpenPGP configuration can't be found
+(for instance, if gpg isn't installed), it now has the same meaning as
+nil.
+
++---
+*** New function 'package-get-version' lets packages query their own version.
+Example use in auctex.el: '(defconst auctex-version (package-get-version))'
+
++---
+*** New 'package-quickstart' feature.
+When 'package-quickstart' is non-nil, package.el precomputes a big
+autoloads file so that activation of packages can be done much faster,
+which can speed up your startup significantly.
+It also causes user options like 'package-user-dir' and
+'package-load-list' to be consulted when 'package-quickstart-refresh'
+is run rather than at startup so you don't need to set them in your
+early init file.
+
++---
+*** New function 'package-activate-all'.
+
++++
+*** New functions for filtering packages list.
+A new function has been added which allows users to filter the
+packages list by name: 'package-menu-filter-by-name'. By default, it
+is bound to '/ n'. Additionally, the function
+'package-menu-filter-by-keyword' has been renamed from
+'package-menu-filter'. Its keybinding has also been changed to '/ k'
+(from 'f'). To clear any of the two filters, the user can now call
+the 'package-menu-clear-filter' function, bound to '/ /' by default.
+
+---
+*** Imenu support has been added to 'package-menu-mode'.
+
+---
+*** The package list can now be sorted by version or description.
+
++++
+*** In Package Menu, 'g' now updates package data from archives.
+Previously, 'g' invoked 'tabulated-list-revert' which did not update
+the cached archive data. It is now bound to 'revert-buffer', which
+will update the data.
+
+'package-menu-refresh' is an obsolete alias for 'revert-buffer'.
+
+** Info
+
++++
+*** Clicking on the left/right arrow icon in the Info tool-bar while
+holding down the Ctrl key pops up a menu of previously visited Info nodes
+where you can select a node to go back (like in browsers).
+
+---
+*** Info can now follow 'file://' protocol URLs.
+The 'file://' URLs in Info documents can now be followed by passing
+them to the 'browse-url' function, like the other protocols: 'ftp',
+'http', and 'https'. This allows to have references to local HTML
+files, for example.
+
+---
+** Display of man pages now limits the width for formatting pages.
+The new user option 'Man-width-max' (80 by default) limits the number
+of columns passed to the 'man' program for formatting man pages. This
+is to enhance readability when man pages are displayed in very wide
+windows (which are customary with today's large displays).
+
+** Xref
+
++++
+*** New command 'xref-find-definitions-at-mouse'.
+This command finds definitions of the identifier at the place of a
+mouse click event, and is intended to be bound to a mouse event.
+
++++
+*** Changing 'xref-marker-ring-length' works after 'xref.el' is loaded.
+Previously, setting 'xref-marker-ring-length' would only take effect
+if set before 'xref.el' was loaded.
+
+---
+*** 'xref-find-definitions' now sets the mark at the buffer position
+where it was invoked.
+
+---
+*** New xref faces 'xref-file-header', 'xref-line-number', 'xref-match'.
+
++---
+*** New user option 'xref-show-definitions-function'.
+It encapsulates the logic pertinent to showing the result of
+'xref-find-definitions'. The user can change it to customize its
+behavior and the display of results.
+
++---
+*** Search results show the buffer even for one hit.
+The search-type Xref commands (e.g. 'xref-find-references' or
+'project-find-regexp') now show the results buffer even when there is
+only one hit. This can be altered by changing
+'xref-show-xrefs-function'.
+
+++++
+*** Xref buffers support refreshing the search results.
+A new command 'xref-revert-buffer' is bound to 'g'.
+
+---
+*** Imenu support has been added to 'xref--xref-buffer-mode'.
+
+** Icomplete
+
++++
+*** New minor mode Fido mode.
+This mode is based on Icomplete, and its name stands for "Fake Ido".
+The point of this mode is to be an 'ido-mode' workalike, but provide
+most of the functionality present in Icomplete that is not in
+'ido-mode', while being much more compatible with all of Emacs's
+completion facilities.
+
+** Ecomplete
+
++---
+*** The ecomplete sorting has changed to a decay-based algorithm.
+This can be controlled by the new 'ecomplete-sort-predicate' user option.
+
++---
+*** The 'ecompleterc' file is now placed in "~/.emacs.d/ecompleterc" by default.
+Of course it will still find it if you have it in "~/.ecompleterc".
+
+** Gnus
+
+---
+*** 'mm-uu-diff-groups-regexp' now defaults to matching all groups,
+which means that "git am" diffs are recognized everywhere.
+
++++
+*** Two new Gnus summary mode navigation commands have been added,
+bound to the '[' and ']' keys: 'gnus-summary-prev-unseen-article' and
+'gnus-summary-next-unseen-article'. These take you (respectively) to
+the previous unseen or next unseen article. (These are the ones that
+are marked with "." in the summary mode lines.)
+
++++
+*** The Gnus user variable 'nnimap-expunge' supports three new values:
+'never' for never expunging messages, 'immediately' for immediately
+expunging deleted messages, and 'on-exit' to expunge deleted articles
+when exiting the group's summary buffer. Setting 'nnimap-expunge' to
+'nil' or 't' is still supported but not recommended, since it may
+result in Gnus expunging all messages that have been flagged as
+deleted by any IMAP client (rather than just those that have been
+deleted by Gnus).
+
++++
- *** Description of variables and functions give an estimated first release.
++*** New user option 'gnus-use-atomic-windows' makes Gnus window layouts atomic.
++See the "Atomic Windows" section of the Elisp manual for details.
+
++++
+*** There's a new value for 'gnus-article-date-headers',
+'combined-local-lapsed', which will show both the time (in the local
+timezone) and the lapsed time.
+
+---
+*** Gnus now maps imaps to 993 only on old MS-Windows versions.
+The nnimap backend used to do this unconditionally to work around
+problems on old versions of MS-Windows. This is now done only for
+Windows XP and older.
+
++++
+*** The nnimap backend now has support for IMAP namespaces.
+This feature can be enabled by setting the new 'nnimap-use-namespaces'
+server variable to non-nil.
+
++++
+*** A prefix argument to 'gnus-summary-limit-to-score' will limit reverse.
+Limit to articles with score at below.
+
++---
+*** The function 'gnus-score-find-favorite-words' has been renamed
+from 'gnus-score-find-favourite-words'.
+
+---
+*** Gmane has been removed as an nnir backend, since Gmane no longer
+has a search engine.
+
++++
+*** Splitting mail on common mailing list headers has been added.
+See the concept index in the Gnus manual for the 'match-list' entry.
+
++++
+*** nil is no longer an allowed value for 'mm-text-html-renderer'.
+
++++
+The default value of 'mm-inline-large-images' has changed from nil to
+'resize', which means that large images will be resized instead of
+displayed with an external program by default.
+
++++
+*** A new Gnus summary mode command, 'S A'
+('gnus-summary-attach-article') can be used to attach the current
+article(s) to a pre-existing Message buffer, or create a new Message
+buffer with the article(s) attached.
+
++++
+*** A new Gnus summary mode command, 'w'
+('gnus-summary-browse-url') scans the article buffer for URLs, and
+offers them to the user to open with 'browse-url'.
+
+---
+*** New user option 'nnir-notmuch-filter-group-names-function'.
+This option controls whether and how to use Gnus search groups as
+'path:' search terms to 'notmuch'.
+
+---
+*** The buttons in the Gnus article buffer were formerly widgets
+(i.e., buttons from widget.el). This has now changed, and they are
+now buttons (from button.el), and commands like 'TAB' now search for
+buttons instead of widgets. There should be no user-visible changes,
+but out-of-tree code that relied on widgets being present might now
+fail.
+
+** erc
+
+---
+*** New hook 'erc-insert-done-hook'.
+This hook is called after strings have been inserted into the buffer,
+and is free to alter point and window configurations, as it's not
+called from inside a 'save-excursion', as opposed to
+'erc-insert-post-hook'.
+
+---
+*** 'erc-button-google-url' has been renamed to 'erc-button-search-url'
+and its value has been changed to Duck Duck Go.
+
+---
+*** 'erc-send-pre-hook' and 'erc-send-this' have been obsoleted.
+The user option to use instead to alter text to be sent is now
+'erc-pre-send-functions'.
+
+** EUDC
+
++---
+*** XEmacs support has been removed.
+
+** eww/shr
+
++++
+*** The new user option 'shr-cookie-policy' can be used to control
+when to use cookies when fetching embedded images. The default is to
+use them when the images are from the same domain as the main HTML
+document.
+
++++
+*** The 'eww' command can now create a new EWW buffer.
+Invoking the command with a prefix argument will cause it to create a
+new EWW buffer for the URL instead of reusing the default one.
+
++++
+*** Clicking with the Ctrl key or 'C-u RET' on a link opens a new tab
+when tab-bar-mode is enabled.
+
++++
+*** The 'd' ('eww-download') command now falls back to current page's URL.
+If this command is invoked with no URL at point, it now downloads the
+current page instead of signaling an error.
+
+*** When opening external links in eww/shr (typically with the
+'C-u RET' keystroke on a link), the link will be flashed with the new
+'shr-selected-link' face to give the user feedback that the command
+has been executed.
+
++++
+*** New user option 'shr-discard-aria-hidden'.
+If set, shr will not render tags with attribute 'aria-hidden="true"'.
+This attribute is meant to tell screen readers to ignore a tag.
+
++++
+*** 'shr-external-browser' has been made into an obsolete alias
+of 'browse-url-secondary-browser-function'.
+
+---
+*** 'shr-tag-ol' now respects the ordered list 'start' attribute.
+
+---
+*** The following tags are now handled: '<code>', '<abbr>', and '<acronym>'.
+
+** Htmlfontify
+
+++++
+*** The functions 'hfy-color', 'hfy-color-vals' and
+'hfy-fallback-color-values' and the variables 'hfy-fallback-color-map'
+and 'hfy-rgb-txt-color-map' have been renamed from names that used
+'colour' instead of 'color'.
+
++++
+** Enriched mode supports the 'charset' text property.
+You can add or modify the 'charset' text properties of text using the
+'Edit->Text Properties->Special Properties' menu, or by invoking the
+'facemenu-set-charset' command. Documents in Enriched mode will be
+saved with the charset properties, and those properties will be
+restored when the file is visited.
+
+** Smtpmail
+
++---
+*** Authentication mechanisms can be added via external packages, by
+defining new 'cl-defmethod' of 'smtpmail-try-auth-method'.
+
+++++
+*** To always force smtpmail to send credentials over on the first
+attempt when communicating with the SMTP server(s), the
+'smtpmail-servers-requiring-authorization' user option can be used.
+
++++
+*** smtpmail will now try resending mail when getting a transient 4xx
+error message from the SMTP server. The new 'smtpmail-retries'
+user option says how many times to retry.
+
+** Footnote mode
+
++---
+*** Support Hebrew-style footnotes
++
++---
+*** Footnote text lines are now aligned.
+Can be controlled via the new user option 'footnote-align-to-fn-text'.
+
+** CSS mode
+
+---
+*** A new command 'css-cycle-color-format' for cycling between color
+formats (e.g. "black" => "#000000" => "rgb(0, 0, 0)") has been added,
+bound to 'C-c C-f'.
+
+---
+*** CSS mode, SCSS mode, and Less CSS mode now have support for Imenu.
+
+** SGML mode
+
+---
+*** 'sgml-quote' now handles double quotes and apostrophes
+when escaping text and in addition all numeric entities when
+unescaping text.
+
+** Python mode
+
+---
+*** Python mode supports three different font lock decoration levels.
+The maximum level is used by default; customize
+'font-lock-maximum-decoration' to tone down the decoration.
+
+---
+*** New user option 'python-pdbtrack-kill-buffers'.
+If non-nil, the default, buffers opened during pdbtracking session are
+killed when pdbtracking session is finished.
+
+---
+*** New function 'python-shell-send-region'.
+It sends the statement delimited by 'python-nav-beginning-of-statement'
+and 'python-nav-end-of-statement' to the inferior Python process.
+
+** Help
+
+---
- previously-set breakpoints. If the code has changed substantially,
- this may not be possible.
++*** Descriptions of variables and functions give an estimated first release
++where the variable or function appeared in Emacs.
+
+---
+*** Output format of 'C-h l' ('view-lossage') has changed.
+For convenience, 'view-lossage' now displays the last keystrokes
+and commands in the same format as the edit buffer of
+'edit-last-kbd-macro'. This makes it possible to copy the lines from
+the buffer generated by 'view-lossage' to the "*Edit Macro*" buffer
+created by 'edit-last-kbd-macro', and to save the macro by 'C-c C-c'.
+
+---
+*** The list of help commands produced by 'C-h C-h' ('help-for-help')
+can now be searched via 'C-s'.
+
+** Ibuffer
+
+---
+*** New filter 'ibuffer-filter-by-process'; bound to '/ E'.
+
+---
+*** All mode filters can now accept a list of symbols.
+This means you can now easily filter several major modes, as well
+as a single mode.
+
+** Search and Replace
+
+++++
+*** Isearch supports a prefix argument for 'C-s' ('isearch-repeat-forward')
+and 'C-r' ('isearch-repeat-backward'). With a prefix argument, these
+commands repeat the search for the specified occurrence of the search string.
+A negative argument repeats the search in the opposite direction.
+This makes possible also to use a prefix argument for 'M-s .'
+('isearch-forward-symbol-at-point') to find the next Nth symbol.
+Also a prefix argument is supported for 'isearch-yank-until-char',
+'isearch-yank-word-or-char', 'isearch-yank-symbol-or-char'.
+
+++++
+*** To go to the first/last occurrence of the current search string
+is possible now with new commands 'isearch-beginning-of-buffer' and
+'isearch-end-of-buffer' bound to 'M-s M-<' and 'M-s M->' in Isearch.
+With a numeric argument, they go to the Nth absolute occurrence
+counting from the beginning/end of the buffer. This complements
+'C-s'/'C-r' that searches for the next Nth relative occurrence
+with a numeric argument.
+
+++++
+*** 'isearch-lazy-count' shows the current match number and total number
+of matches in the Isearch prompt. User options
+'lazy-count-prefix-format' and 'lazy-count-suffix-format' define the
+format of the current and the total number of matches in the prompt's
+prefix and suffix respectively.
+
++---
+*** 'lazy-highlight-buffer' highlights matches in the full buffer.
+It is useful in combination with 'lazy-highlight-cleanup' customized to nil
+to leave matches highlighted in the whole buffer after exiting isearch.
+Also when 'lazy-highlight-buffer' prepares highlighting in the buffer,
+navigation through the matches without flickering is more smooth.
+'lazy-highlight-buffer-max-at-a-time' controls the number of matches to
+highlight in one iteration while processing the full buffer.
+
++++
+*** New isearch bindings.
+
+'C-M-z' invokes new function 'isearch-yank-until-char', which yanks
+everything from point up to but not including the specified
+character into the search string. This is especially useful for
+keyboard macros.
+
+'C-M-w' in isearch changed from 'isearch-del-char' to the new function
+'isearch-yank-symbol-or-char'. 'isearch-del-char' is now bound to
+'C-M-d'.
+
++++
+'M-s h l' invokes 'highlight-lines-matching-regexp' using the search
+string to highlight lines matching the search string. This is similar
+to the existing binding 'M-s h r' ('highlight-regexp') that highlights
+JUST the search string.
+
++++
+*** New user option 'isearch-yank-on-move' provides options 't' and 'shift'
+to extend the search string by yanking text that ends at the new
+position after moving point in the current buffer. 'shift' extends
+the search string by motion commands while holding down the shift key.
+
+++++
+*** 'isearch-allow-scroll' provides new option 'unlimited' to allow
+scrolling any distance off screen.
+
+---
+*** Isearch now remembers the regexp-based search mode for words/symbols
+and case-sensitivity together with search strings in the search ring.
+
+---
+*** Isearch now has its own tool-bar and menu-bar menu.
+
++++
+*** 'flush-lines' prints and returns the number of deleted matching lines.
+
+---
+*** 'char-fold-to-regexp' now matches more variants of a base character.
+The table used to check for equivalence of characters is now built
+using the complete chain of unicode decompositions of a character,
+rather than stopping after one level, such that searching for
+e.g. "GREEK SMALL LETTER IOTA" will now also find "GREEK SMALL LETTER
+IOTA WITH OXIA".
+
++++
+*** New char-folding options: 'char-fold-include' lets you add ad hoc
+foldings, 'char-fold-exclude' to remove foldings from default decomposition,
+and 'char-fold-symmetric' to search for any of an equivalence class of
+characters. For example, with a 'nil' value of 'char-fold-symmetric'
+you can search for "e" to find "é", but not vice versa. With a non-nil
+value you can search for either, for example, you can search for "é"
+to find "e".
+
+** Debugger
+
++++
+*** The Lisp Debugger is now based on 'backtrace-mode'.
+Backtrace mode adds fontification and commands for changing the
+appearance of backtrace frames. See the node "(elisp) Backtraces" in
+the Elisp manual for documentation of the new mode and its commands.
+
+** Edebug
+
++++
+*** 'edebug-eval-last-sexp' and 'edebug-eval-print-last-sexp' interactively
+now take a zero prefix analogously to the non-Edebug counterparts.
+
++++
+*** New faces 'edebug-enabled-breakpoint' and 'edebug-disabled-breakpoint'.
+When setting breakpoints in Edebug, an overlay with these faces are
+placed over the point in question, depending on whether they are
+enabled or not.
+
++++
+*** New command 'edebug-toggle-disable-breakpoint'.
+This command allows you to disable a breakpoint temporarily. This is
+mainly useful with breakpoints that are conditional and would take
+some time to recreate.
+
++++
+*** New command 'edebug-unset-breakpoints'.
+To clear all breakpoints in the current form, the 'U' command in
+'edebug-mode', or 'M-x edebug-unset-breakpoints' can be used.
+
+---
+*** Re-instrumenting a function with Edebug will now try to preserve
- Snake and Pong are more playable on HiDPI displays.
++previously-set breakpoints. However, if the code has changed
++substantially, this may not be possible.
+
++++
+*** New command 'edebug-remove-instrumentation'.
+This command removes Edebug instrumentation from all functions that
+have been instrumented.
+
++++
+*** The runtime behavior of Edebug's instrumentation can be changed
+using the new variables 'edebug-behavior-alist',
+'edebug-after-instrumentation-function' and
+'edebug-new-definition-function'. Edebug's behavior can be changed
+globally or for individual definitions.
+
++++
+*** Edebug's backtrace buffer now uses 'backtrace-mode'.
+Backtrace mode adds fontification, links and commands for changing the
+appearance of backtrace frames. See the node "(elisp) Backtraces" in
+the Elisp manual for documentation of the new mode and its commands.
+
+The binding of 'd' in Edebug's keymap is now 'edebug-pop-to-backtrace'
+which replaces 'edebug-backtrace'. Consequently Edebug's backtrace
+windows now behave like those of the Lisp Debugger and of ERT, in that
+when they appear they will be the selected window.
+
+The new 'backtrace-goto-source' command, bound to 's', works in
+Edebug's backtraces on backtrace frames whose source code has
+been instrumented by Edebug.
+
+** Enhanced xterm support
+
++---
+*** New user option 'xterm-set-window-title' controls whether Emacs sets
+the XTerm window title. This feature is experimental and is disabled
+by default.
+
+** Grep
+
++++
+*** 'rgrep', 'lgrep' and 'zrgrep' now hide part of the command line
+that contains a list of ignored directories and files.
+Clicking on the button with ellipsis unhides it.
+The abbreviation can be disabled by the new user option
+'grep-find-abbreviate'. The new command
+'grep-find-toggle-abbreviation' toggles it interactively.
+
++---
+*** 'grep-find-use-xargs' is now customizable with sorting options.
+
+** ERT
+
++++
+*** New variable 'ert-quiet' allows to make ERT output in batch mode
+less verbose by removing non-essential information.
+
++++
+*** ERT's backtrace buffer now uses 'backtrace-mode'.
+Backtrace mode adds fontification and commands for changing the
+appearance of backtrace frames. See the node "(elisp) Backtraces" in
+the Elisp manual for documentation of the new mode and its commands.
+
+** Gamegrid
+
+---
+*** Gamegrid now determines its default glyph size based on display
+dimensions, instead of always using 16 pixels. As a result, Tetris,
- *** 'thread-join' returns the result of the finished thread now.
++Snake and Pong are better playable on HiDPI displays.
+
+---
+*** 'gamegrid-add-score' can now sort scores from lower to higher.
+This is useful for games where lower scores are better, like time-based games.
+
+** Filecache
+
+---
+*** Completing filenames in the minibuffer via 'C-TAB' now uses the
+styles as configured by the user option 'completion-styles'.
+
+** New macros 'thunk-let' and 'thunk-let*'.
+These macros are analogue to 'let' and 'let*', but create bindings that
+are evaluated lazily.
+
+** next-error
+
++++
+*** New user option 'next-error-find-buffer-function'.
+The value should be a function that determines how to find the
+next buffer to be used by 'next-error' and 'previous-error'. The
+default is to use the last buffer that navigated to the current
+error.
+
++++
+*** New command 'next-error-select-buffer'.
+It can be used to set any buffer as the next one to be used by
+'next-error' and 'previous-error'.
+
+** nxml-mode
+
+---
+*** The default value of 'nxml-sexp-element-flag' is now t.
+This means that pressing 'C-M-SPACE' now selects the entire tree by
+default, and not just the opening element.
+
+** Eshell
+
++---
+*** TAB completion uses the standard 'completion-at-point' rather than
+'pcomplete'. Its UI is slightly different but can be customized to
+behave similarly, e.g. Pcomplete's default cycling can be obtained
+with '(setq completion-cycle-threshold 5)'.
+
+---
+*** Eshell no longer re-initializes its keymap every call.
+This allows users to use (define-key eshell-mode-map ...) as usual.
+Some modules have their own minor mode now to account for these
+changes.
+
++++
+*** Expansion of history event designators is disabled by default.
+To restore the old behavior, use
+
+ (add-hook 'eshell-expand-input-functions
+ #'eshell-expand-history-references)
+
+---
+*** The function 'eshell-uniquify-list' has been renamed from
+'eshell-uniqify-list'.
+
++---
+*** The function 'eshell/kill' is now able to handle signal switches.
+Previously 'eshell/kill' would fail if provided a kill signal to send
+to the process. It now accepts signals specified either by name or by
+its number.
+
+---
+*** Emacs now follows symlinks in history-related files.
+The files specified by 'eshell-history-file-name' and
+'eshell-last-dir-ring-file-name' can include symlinks; these are now
+followed when Emacs writes the relevant history variables to the disk.
+
+** Shell
+
+---
+*** Program name completion inside remote shells works now as expected.
+
++++
+*** The user option 'shell-file-name' can be set now as connection-local
+variable for remote shells. It still defaults to "/bin/sh".
+
+** Single shell commands
+
++++
+*** 'async-shell-command-width' defines the number of display columns
+available for output of asynchronous shell commands.
+
++++
+*** Prompt for shell commands can now show the current directory.
+Customize the new user option 'shell-command-prompt-show-cwd' to enable it.
+
+** Pcomplete
+
++---
+*** The 'pcomplete' command is now obsolete.
+The Pcomplete functionality can be obtained via 'completion-at-point'
+instead, by adding 'pcomplete-completions-at-point' to
+'completion-at-point-functions'.
+
++---
+*** The function 'pcomplete-uniquify-list' has been renamed from
+'pcomplete-uniqify-list'.
+
+---
+*** 'pcomplete/make' now completes on targets in included files, recursively.
+To recover the previous behavior, set new user option
+'pcmpl-gnu-makefile-includes' to nil.
+
+** Auth-source
+
+---
+*** The Secret Service backend supports the ':create' key now.
+
++---
+*** ".authinfo" and ".netrc" files now use a new mode: 'authinfo-mode'.
+This is just like 'fundamental-mode', except that it hides passwords
+under a "****" display property. When the cursor moves to this text,
+the real password is revealed (via 'reveal-mode'). The new
+'authinfo-hidden' user option can be used to control what to hide.
+
+** Tramp
+
++++
+*** New connection method "nextcloud", which allows to access OwnCloud
+or NextCloud hosted files and directories.
+
++++
+*** New connection method "rclone", which allows to access system
+storages via the 'rclone' program. This feature is experimental.
+
++++
+*** New connection method "sudoedit", which allows to edit local files
+with different user credentials. Contrary to the "sudo" method, no
+session is run permanently in the background. This is for security
+reasons.
+
++++
+*** Connection methods "obex" and "synce" are removed, because they
+are obsoleted in GVFS.
+
++++
+*** Validated passwords are saved by auth-source backends which support this.
+
++++
+*** During user and host name completion in the minibuffer, results
+from auth-source search are taken into account. This can be disabled
+by setting the user option 'tramp-completion-use-auth-sources' to nil.
+
++++
+*** The user option 'tramp-ignored-file-name-regexp' allows to disable
+Tramp for some look-alike remote file names.
+
++++
+*** For some connection methods, like "su" or "sudo", the host name in
+ad-hoc multi-hop file names must match the previous hop. Default host
+names are adjusted to the host name from the previous hop.
+
++++
+*** For the connection methods "sudo" and "doas" there exists a
+timeout, after which the underlying session is disabled. This is for
+security reasons.
+
++++
+*** For some connection methods, like "sshx" or "plink", it is
+possible to configure the remote login shell. This avoids problems
+with remote hosts, where "/bin/sh" is a link to a shell which
+cooperates badly with Tramp.
+
++++
+*** New commands 'tramp-rename-files' and 'tramp-rename-these-files'.
+They allow to save remote files somewhere else when the corresponding
+host is not reachable anymore.
+
+** Rcirc
+
+---
+*** New user option 'rcirc-url-max-length'.
+Setting this option to an integer causes URLs displayed in Rcirc
+buffers to be truncated to that many characters.
+
+---
+*** The default '/quit' and '/part' reasons are now configurable.
+Two new user options are provided for this:
+'rcirc-default-part-reason' and 'rcirc-default-quit-reason'.
+
+** Register
+
+---
+*** The return value of method 'register-val-describe' includes the
+names of buffers shown by the windows of a window configuration.
+
+---
+** The options.el library has been removed.
+It was obsolete since Emacs 22.1, replaced by customize.
+
++---
+** The tls.el and starttls.el libraries are now marked obsolete.
+Use of built-in libgnutls based functionality (described in the Emacs
+GnuTLS manual) is recommended instead.
+
+** Message
+
++---
+*** Completion of email addresses can use the standard completion UI.
+This is controlled by 'message-expand-name-standard-ui'.
+With the standard UI the different sources (ecomplete, bbdb, and eudc)
+are matched together and try to obey 'completion-styles'.
+It should work for other completion front ends like Company.
+
++---
+*** 'message-mode' now supports highlighting citations of different depths.
+This can be customized via the new user option
+'message-cite-level-function' and the new 'message-cited-text-*' faces.
+
++++
+*** Messages can now be systematically encrypted
+when the PGP keyring contains a public key for every recipient. To
+achieve this, add 'message-sign-encrypt-if-all-keys-available' to
+'message-send-hook'.
+
+---
+*** When replying a message that have addresses on the form
+'"foo@bar.com" <foo@bar.com>', Message will elide the repeated "name"
+from the address field in the response.
+
+---
+*** The default of 'message-forward-as-mime' has changed from t to nil
+as it has been reported that many recipients can't read forwards that
+are formatted as MIME digests.
+
++++
+*** 'message-forward-included-headers' has changed its default to
+exclude most headers when forwarding.
+
+*** 'mml-secure-openpgp-sign-with-sender' sets also "gpg --sender"
+When 'mml-secure-openpgp-sign-with-sender' is non-nil message sender's
+email address (in addition to its old behavior) will also be used to
+set gpg's "--sender email@domain" option.
+
+The option is useful for two reasons when verifying the signature:
+
+ 1. GnuPG's TOFU statistics are updated for the specific user id
+ (email) only. See gpg(1) man page about "--sender".
+
+ 2. GnuPG's '--auto-key-retrieve' functionality can use WKD (web key
+ directory) method for finding the signer's key. You need GnuPG
+ 2.2.17 to fully benefit from this feature. See gpg(1) man page for
+ '--auto-key-retrieve'.
+
+---
+** EasyPG
+
+---
+*** 'epa-pinentry-mode' is renamed to 'epg-pinentry-mode'.
+It now applies to epg functions as well as epa functions.
+
+---
+*** The alias functions 'epa--encode-coding-string',
+'epa--decode-coding-string', and 'epa--select-safe-coding-system' have
+been removed. Use 'encode-coding-string', 'decode-coding-string', and
+'select-safe-coding-system' instead.
+
++---
+*** 'epg-context' structure supports now 'sender' slot.
+The value of the new 'sender' slot (if a string) is used to set gpg's
+'--sender' option. This feature is used by
+'mml-secure-openpgp-sign-with-sender'. See gpg(1) manual page about
+'--sender' for more information.
+
+---
+** Rmail
+
++++
+*** New user option 'rmail-output-reset-deleted-flag'.
+If this option is non-nil, messages appended to an output file by the
+'rmail-output' command have their Deleted flag reset.
+
++---
+*** The command 'rmail-summary-by-senders' with an empty argument
+selects the messages to summarize with a regexp that matches the
+sender of the current message.
+
+** Threads
+
++++
+*** New variable 'main-thread' holds Emacs's main thread.
+This is handy in Lisp programs that run on a non-main thread and want
+to signal the main thread, e.g., when they encounter an error.
+
++++
- bookmark-grok-file-format-version, bookmark-maybe-upgrade-file-format,
- bookmark-upgrade-file-format-from-0, bookmark-upgrade-version-0-alist
++*** 'thread-join' now returns the result of the finished thread.
+
++++
+*** 'thread-signal' does not propagate errors to the main thread.
+Instead, error messages are just printed in the main thread.
+
+---
+*** 'thread-alive-p' is now obsolete, use 'thread-live-p' instead.
+
++++
+*** New command 'list-threads' shows Lisp threads.
+See the current list of live threads in a tabulated-list buffer which
+automatically updates. In the buffer, you can use 's q' or 's e' to
+signal a thread with quit or error respectively, or get a snapshot
+backtrace with 'b'.
+
+** thingatpt.el
+
+---
+*** 'thing-at-point' supports a new "thing" called 'uuid'.
+A symbol 'uuid' can be passed to 'thing-at-point' and it returns the
+UUID at point.
+
+---
+*** 'number-at-point' will now recognize hex numbers like 0xAb09 and #xAb09
+and return them as numbers.
+
+---
+*** 'word-at-point' and 'sentence-at-point' accept NO-PROPERTIES.
+Just like 'thing-at-point' itself.
+
+** Interactive automatic highlighting
+
++++
+*** 'highlight-regexp' can now highlight subexpressions.
+The new command accepts a prefix numeric argument to choose the
+subexpression.
+
+** Mouse display of minor mode menu
+
+---
+*** 'minor-mode-menu-from-indicator' now displays full minor mode name.
+When there is no menu for a mode, display the mode name after the
+indicator instead of just the indicator (which is sometimes cryptic).
+
+** rx
+
+---
+*** rx now handles raw bytes in character alternatives correctly,
+when given in a string. Previously, '(any "\x80-\xff")' would match
+characters U+0080...U+00FF. Now the expression matches raw bytes in
+the 128...255 range, as expected.
+
+---
+*** The rx 'or' and 'seq' forms no longer require any arguments.
+'(or)' produces a regexp that never matches anything, while '(seq)'
+matches the empty string, each being an identity for the operation.
+This also works for their aliases: '|' for 'or'; ':', 'and' and
+'sequence' for 'seq'.
+The symbol 'unmatchable' can be used as an alternative to '(or)'.
+
+---
+*** 'regexp' and new 'literal' accept arbitrary lisp as arguments.
+In this case, 'rx' will generate code which produces a regexp string
+at run time, instead of a constant string.
+
+---
+*** New rx extension mechanism: 'rx-define', 'rx-let', 'rx-let-eval'.
+These macros add new forms to the rx notation.
+
++++
+*** 'anychar' is now an alias for 'anything'.
+Both match any single character; 'anychar' is more descriptive.
+
++++
+*** New 'intersection' form for character sets.
+With 'or' and 'not', it can be used to compose character-matching
+expressions from simpler parts.
+
++++
+*** 'not' argument can now be a character or single-char string.
+
+** Frames
+
++++
+*** New command 'make-frame-on-monitor' makes a frame on the specified monitor.
+
++++
+*** New value of 'minibuffer' frame parameter 'child-frame'.
+This allows to create and parent immediately a minibuffer-only child
+frame when making a frame.
+
+---
+*** New predicates 'display-blink-cursor-p' and 'display-symbol-keys-p'.
+These predicates are to be preferred over 'display-graphic-p' when
+testing for blinking cursor capability and the capability to have
+symbols (e.g., '[return]', '[tab]', '[backspace]') as keys respectively.
+
+** Tabulated List mode
+
++++
+*** New user options for tabulated list sort indicators.
+You can now customize which sorting indicator character to display
+near the current column in Tabulated Lists (see user options
+'tabulated-list-gui-sort-indicator-asc',
+'tabulated-list-gui-sort-indicator-desc',
+'tabulated-list-tty-sort-indicator-asc', and
+'tabulated-list-tty-sort-indicator-desc').
+
++++
+*** Two new commands and keystrokes have been added to the tabulated
+list mode: 'w' (which widens the current column) and 'c' which makes
+the current column contract.
+
++++
+*** New function 'tabulated-list-clear-all-tags'.
+This function clears all tags from the padding area in the current
+buffer. Tags are typically added by calling 'tabulated-list-put-tag'.
+
+** Text mode
+
++++
+*** 'text-mode-variant' is now obsolete, use 'derived-mode-p' instead.
+
+** CUA mode
+
+---
+*** New user option 'cua-rectangle-terminal-modifier-key'.
+This user option allows for the customization of the modifier key used
+in a terminal frame.
+
+** JS mode
+
+---
+*** JSX syntax is now automatically detected and enabled.
+If a file imports Facebook's 'React' library, or if the file uses the
+extension '.jsx', then various features supporting XML-like syntax
+will be supported in 'js-mode' and derivative modes. ('js-jsx-mode'
+no longer needs to be enabled.)
+
+---
+*** New user option 'js-jsx-detect-syntax' disables automatic detection.
+This is turned on by default.
+
+---
+*** New user option 'js-jsx-syntax' enables JSX syntax unconditionally.
+This is off by default.
+
+---
+*** New variable 'js-jsx-regexps' controls JSX detection.
+
+---
+*** JSX syntax is now highlighted like SGML.
+
+---
+*** JSX code is properly indented in many more scenarios.
+Previously, JSX indentation usually only worked when an element was
+wrapped in parenthesis (e.g. in a 'return' statement or a function
+call). It would also fail in many intricate cases. Now, indentation
+should work anywhere without parenthesis; many more intricacies are
+supported; and, indentation conventions align more closely with those
+of the React developer community (see 'js-jsx-align->-with-<'),
+otherwise still adhering to SGML conventions.
+
+---
+*** New user option 'js-jsx-align->-with-<' controls '>' indents.
+Commonly in JSX code, a '>' on its own line is indented at the same
+level as its opening '<'. This is the new default for JSX. This
+behavior is slightly different than that used by SGML in Emacs, where
+'>' is indented at the same level as attributes, which was also the
+old default for JSX.
+
+This is turned on by default. To get back the old default indentation
+behavior of aligning '>' with attributes, set 'js-jsx-align->-with-<'
+to nil.
+
+---
+*** Indentation uses 'js-indent-level' instead of 'sgml-basic-offset'.
+Since JSX is a syntax extension of JavaScript, it makes the most sense
+for JSX expressions to be indented the same number of spaces as other
+JS expressions. This is a breaking change, but it probably aligns
+with how you'd expect this indentation to behave. If you want JSX to
+be indented like JS, you won't need to change your config.
+
+The old behavior can be emulated by controlling JSX indentation
+independently of JS, by setting 'js-jsx-indent-level'.
+
+---
+*** New user option 'js-jsx-indent-level' for different JSX indentation.
+If you wish to indent JSX by a different number of spaces than JS, set
+this user option to the desired number.
+
+---
+*** New user option 'js-jsx-attribute-offset' for JSX attribute indents.
+
+---
+*** New variable 'js-syntactic-mode-name' controls mode name display.
+Previously, the mode name was simply 'JavaScript'. Now, when a syntax
+extension like JSX is enabled, the mode name is 'JavaScript[JSX]'.
+Set this variable to nil to disable the new behavior.
+
+---
+*** New function 'js-use-syntactic-mode-name' for deriving modes.
+Packages deriving from 'js-mode' with 'define-derived-mode' should
+call this function to add enabled syntax extensions to their mode
+name, too.
+
+** Autorevert
+
+++++
+*** New user option 'auto-revert-avoid-polling' for saving power.
+When set to a non-nil value, buffers in Auto Revert mode are no longer
+polled for changes periodically. This reduces the power consumption
+of an idle Emacs, but may fail on some network file systems; set
+'auto-revert-notify-exclude-dir-regexp' to match files where
+notification is not supported. The default value is nil.
+
+++++
+*** New variable 'buffer-auto-revert-by-notification'
+A major mode can declare that notification on the buffer's default
+directory is sufficient to know when updates are required, by setting
+the new variable 'buffer-auto-revert-by-notification' to a non-nil
+value. Auto Revert mode can use this information to avoid polling the
+buffer periodically when 'auto-revert-avoid-polling' is non-nil.
+
+---
+*** 'global-auto-revert-ignore-buffer' can now also be a predicate
+function that can be used for more fine-grained control of which
+buffers to auto-revert.
+
+** auth-source-pass
+
++++
+*** New user option 'auth-source-pass-filename'.
+Allows setting the path to the password-store, defaults to
+"~/.password-store".
+
++++
+*** New user option 'auth-source-pass-port-separator'.
+Specifies separator between host and port, defaults to colon ":".
+
+---
+*** Minimize the number of decryptions during password lookup.
+This makes the package usable with physical tokens requiring touching
+a sensor for every decryption.
+
+---
+*** 'auth-source-pass-get' is now autoloaded.
+
+** Bookmarks
+
+---
+*** 'bookmark-file' and 'bookmark-old-default-file' are now obsolete
+aliases of 'bookmark-default-file'.
+
++---
+*** New user option 'bookmark-watch-bookmark-file'.
+When non-nil, watch whether the bookmark file has changed on disk.
+
+---
+*** The old bookmark file format is no longer supported.
+This bookmark file format has not been used in Emacs since at least
+version 19.34, released in 1996, and will no longer be automatically
+converted to the new bookmark file format.
+
+The following functions are now declared obsolete:
- *** Tab Bar mode
++'bookmark-grok-file-format-version',
++'bookmark-maybe-upgrade-file-format',
++'bookmark-upgrade-file-format-from-0', and
++'bookmark-upgrade-version-0-alist'.
+
+---
+** The mantemp.el library is now marked obsolete.
+This library generates manual C++ template instantiations. It should
+no longer be useful on modern compilers, which do this automatically.
+
+** Ispell
+
+---
+*** New hook 'ispell-change-dictionary-hook'.
+This runs after changing the dictionary and could be used to
+automatically spellcheck a buffer when changing language without
+needing to advice 'ispell-change-dictionary'.
+
+** scroll-lock
+
+---
+*** New command 'scroll-lock-next-line-always-scroll'.
+This command is bound to 'S-down' and scrolls the buffer up in
+particular when the end of the buffer is visible in the window.
+
+** mwheel.el
+
+---
+*** 'mwheel-install' is now obsolete.
+Use 'mouse-wheel-mode' instead. Note that 'mouse-wheel-mode' is
+already enabled by default on most graphical displays.
+
+** Gravatar
+
++++
+*** 'gravatar-cache-ttl' is now a number of seconds.
+The previously used timestamp format of a list of integers is still
+supported, but is deprecated. The default value has not changed.
+
++++
+*** 'gravatar-size' can now be nil.
+This results in the use of Gravatar's default size of 80 pixels.
+
++++
+*** The default fallback gravatar is now configurable.
+This is possible using the new user options 'gravatar-default-image'
+and 'gravatar-force-default'.
+
+** ada-mode
+
++---
+*** The built-in ada-mode is now deleted. The GNU ELPA package is a
+good replacement, even in very large source files.
+
+** time-stamp
+
++---
+*** New '%5z' conversion for 'time-stamp-format' gives time zone offset.
+Specifying '%5z' in 'time-stamp-format' or 'time-stamp-pattern'
+expands to the time zone offset, e.g., '+0100'. The time zone used is
+specified by 'time-stamp-time-zone'.
+
+Because this feature is new in Emacs 27.1, do not use it in the local
+variables section of any file that might be edited by an older version
+of Emacs.
+
++---
+*** Some conversions recommended for 'time-stamp-format' have changed.
+The new documented/recommended %-conversions are closer to those
+used by 'format-time-string' and are compatible at least as far back
+as Emacs 22.1 (released in 2007).
+
+Uppercase abbreviated day name of week: was %3A, now %#a
+Full day name of week: was %:a, now %:A
+Uppercase abbreviated month name: was %3B, now %#b
+Full month name: was %:b, now %:B
+Four-digit year: was %:y, now %Y
+Lowercase timezone name: was %z, now %#Z
+Fully-qualified host name: was %s, now %Q
+Unqualified host name: (was none), now %q
+Login name: was %u, now %l
+User's full name: was %U, now %L
+
+Merely having '(add-hook 'before-save-hook 'time-stamp)' in your
+Emacs init file does not expose you to this change. However,
+if you set 'time-stamp-format' or 'time-stamp-pattern' with a
+file-local variable, you may need to update the value.
+
+** mode-local
++---
+*** Declare 'define-overload' and 'define-child-mode' as obsolete.
++
++---
+*** Rename several internal functions to use a 'mode-local-' prefix.
+
+** CC Mode
+
++++
+*** You can now flag "wrong style" comments with 'font-lock-warning-face'.
+To do this, use 'c-toggle-comment-style', if needed, to set the desired
+default comment style (block or line); then set the user option
+'c-mark-wrong-style-of-comment' to non-nil.
+
+\f
+* New Modes and Packages in Emacs 27.1
+
+** Tab Bars
+
++++
- Formerly, these functions often (though not always) returned nil.
- For example, if there is an access error, I/O error or low-level
++*** Tab Bar mode.
+The new command 'tab-bar-mode' enables the tab bar at the top of each
+frame, where you can use tabs to switch between named persistent
+window configurations.
+
+The 'C-x t' sequence is the new prefix key for tab-related commands:
+'C-x t 2' creates a new tab; 'C-x t 0' deletes the current tab;
+'C-x t b' switches to buffer in another tab; 'C-x t f' and 'C-x t C-f'
+edit file in another tab; and 'C-TAB' and 'S-C-TAB' switch to the next
+or previous tab. You can also switch between tabs and create/delete
+tabs with a mouse.
+
+Tab-related commands are available even when 'tab-bar-mode' is
+disabled: by default, they enable 'tab-bar-mode' in that case.
+
+The X resource "tabBar", class "TabBar" enables the tab bar
+when its value is "on", "yes" or "1".
+
+The user option 'tab-bar-position' specifies where to show the tab bar.
+
+Read the new Info node "(emacs) Tab Bars" for full description
+of all related features.
+
+++++
+*** Tab Line mode
+The new command 'global-tab-line-mode' enables the tab line above each
+window, which you can use to switch buffers in the window. Selecting
+the previous window-local tab is the same as typing 'C-x <LEFT>'
+('previous-buffer'), selecting the next tab is the same as 'C-x <RIGHT>'
+('next-buffer'). Both commands support a numeric prefix argument as
+a repeat count. Clicking on the plus icon adds a new buffer to the
+window-local tab line of buffers. Using the mouse wheel on the tab
+line scrolls tabs.
+
+++++
+** fileloop.el lets one setup multifile operations like search&replace.
+
++++
+** Emacs can now visit files in archives as if they were directories.
+This feature uses Tramp and works only on systems which support GVFS,
+i.e. GNU/Linux, roughly spoken. See the node "(tramp) Archive file
+names" in the Tramp manual for full documentation of these facilities.
+
++++
+** New library for writing JSONRPC applications (https://jsonrpc.org).
+The 'jsonrpc' library enables writing Emacs Lisp applications that
+rely on this protocol. Since the protocol is designed to be
+transport-agnostic, the library provides an API to implement new
+transport strategies as well as a separate API to use them. A
+transport implementation for process-based communication, such as is
+used by the Language Server Protocol (LSP), is readily available.
+
++++
+** Backtrace mode improves viewing of Elisp backtraces.
+Backtrace mode adds pretty printing, fontification and ellipsis
+expansion to backtrace buffers produced by the Lisp debugger, Edebug
+and ERT. See the node "(elisp) Backtraces" in the Elisp manual for
+documentation of the new mode and its commands.
+
++++
+** so-long.el helps to mitigate performance problems with long lines.
+When 'global-so-long-mode' has been enabled, visiting a file with very
+long lines will (subject to configuration) cause the user's preferred
+'so-long-action' to be automatically invoked (by default, the buffer's
+major mode is replaced by 'so-long-mode'). In extreme cases this can
+prevent delays of several minutes, and make Emacs responsive almost
+immediately. Type 'M-x so-long-commentary' for full documentation.
+
+\f
+* Incompatible Lisp Changes in Emacs 27.1
+
+---
+** Incomplete destructive splicing support has been removed.
+Support for Common Lisp style destructive splicing (",.") was
+incomplete and broken for a long time. It has now been removed.
+
+This means that backquote substitution now works for identifiers
+starting with a period ("."). Consider the following example:
+
+ (let ((.foo 42)) `,.foo)
+
+In the past, this would have incorrectly evaluated to '(\,\. foo)',
+but will now instead evaluate to '42'.
+
+---
+** The REGEXP in 'magic-mode-alist' is now matched case-sensitively.
+Likewise for 'magic-fallback-mode-alist'.
+
++++
+** 'add-hook' does not always add to the front or the end any more.
+The replacement of 'append' with 'depth' implies that the function is
+not always added to the very front (when append/depth is nil) or the
+very end (when append/depth is t) any more because other functions on
+the hook may have specified higher/lower depths. This makes it
+possible to control the ordering of functions more precisely, as was
+already possible in 'add-function' and 'advice-add'.
+
++---
+** In 'compilation-error-regexp-alist' the old undocumented feature
+where 'line' could be a function of 2 arguments has been dropped.
+
++---
+** 'define-fringe-bitmap' is always defined, even when Emacs is built
+without any GUI support.
+
+---
+** Just loading a theme's file no longer activates the theme's settings.
+Loading a theme with 'M-x load-theme' still activates the theme, as it
+did before. However, loading the theme's file with 'M-x load-file',
+or using 'require' or 'load' in a Lisp program, doesn't actually apply
+the theme's settings until you either invoke 'M-x enable-theme' or
+type 'M-x load-theme'. (In a Lisp program, calling 'enable-theme' or
+invoking 'load-theme' with NO-ENABLE argument omitted or nil has the
+same effect of activating a theme whose file has been loaded.) The
+special case of the 'user' theme is an exception: it is frequently
+used for ad-hoc customizations, so the settings of that theme are by
+default applied immediately.
+
+The variable 'custom--inhibit-theme-enable' controls this behavior;
+its default value changed in Emacs 27.1.
+
++---
+** The REPETITIONS argument of 'benchmark-run' can now also be a variable.
+
++---
+** Interpretation of relative 'HOME' directory has changed.
+If "$HOME" is set to a relative file name, 'expand-file-name' now
+interprets it relative to the directory where Emacs was started, not
+relative to the 'default-directory' of the current buffer. We recommend
+always setting "$HOME" to an absolute file name, so that its meaning is
+independent of where Emacs was started.
+
++---
+** 'file-name-absolute-p' no longer considers "~foo" to be an absolute
+file name if there is no user named "foo".
+
+++++
+** The FILENAME argument to 'file-name-base' is now mandatory and no
+longer defaults to 'buffer-file-name'.
+
++++
+** File metadata primitives now signal an error if I/O, access, or
+other serious errors prevent them from determining the result.
- +++
- ** New macro 'benchmark-progn'.
- This macro works like 'progn', but messages how long it takes to
- evaluate the body forms. The value of the last form is the return
- value.
-
- +++
- ** New function 'read-char-from-minibuffer'.
- This function works like 'read-char', but uses 'read-from-minibuffer'
- to read a character, so it maintains a history that can be navigated
- via usual minibuffer keystrokes 'M-p'/'M-n'.
-
- ** New variables 'set-message-function' and 'clear-message-function'
- can be used to specify functions to show and clear messages that
- normally are displayed in the echo area.
-
- ** 'setq-local' can now set an arbitrary number of variables, which
- makes the syntax more like 'setq'.
-
- ** 'reveal-mode' can now also be used for more than to toggle between
- invisible and visible: It can also toggle 'display' properties in
- overlays. This is only done on 'display' properties that have the
- 'reveal-toggle-invisible' property set.
-
- +++
- ** 'process-contact' now takes an optional NO-BLOCK argument to allow
- not waiting for a process to be set up.
-
- ---
- ** New variable 'read-process-output-max' controls sub-process throughput.
- This variable determines how many bytes can be read from a sub-process
- in one read operation. The default, 4096 bytes, was previously a
- hard-coded constant. Setting it to a larger value might enhance
- throughput of reading from sub-processes that produces vast
- (megabytes) amounts of data in one go.
-
- +++
- ** The new user option 'quit-window-hook' is now run first when
- executing the 'quit-window' command.
-
- ** The user options 'help-enable-completion-auto-load',
- 'help-enable-auto-load' and 'vhdl-project-auto-load', as well as the
- function 'vhdl-auto-load-project' have been renamed to have "autoload"
- without the hyphen in their names. Obsolete aliases from the old
- names have been added.
-
- +++
- ** Buttons (created with 'make-button' and related functions) can
- now use the 'button-data' property. If present, the data in this
- property will be passed on to the 'action' function instead of the
- button itself in 'button-activate'.
-
- ** 'defcustom' now takes a ':local' keyword that can be either t or
- 'permanent', which mean that the variable should be automatically
- buffer-local. 'permanent' also sets the variable's 'permanent-local'
- property.
-
- +++
- ** The new macro 'with-suppressed-warnings' can be used to suppress
- specific byte-compile warnings.
-
- +++
- ** The new macro 'ignore-error' is like 'ignore-errors', but takes a
- specific error condition, and will only ignore that condition. (This
- can also be a list of conditions.)
-
- ---
- ** The new function 'byte-compile-info-message' can be used to output
- informational messages that look pleasing during the Emacs build.
-
- ---
- ** New 'help-fns-describe-variable-functions' hook.
- Makes it possible to add metadata information to 'describe-variable'.
-
- ** i18n (internationalization)
-
- *** ngettext can be used now to return the right plural form
- according to the given numeric value.
-
- +++
- ** 'inhibit-null-byte-detection' is renamed to 'inhibit-nul-byte-detection'.
-
- +++
- ** 'self-insert-command' takes the char to insert as (optional) argument.
-
- ** 'lookup-key' can take a list of keymaps as argument.
-
- +++
- ** 'condition-case' now accepts 't' to match any error symbol.
-
- +++
- ** New function 'proper-list-p'.
- Given a proper list as argument, this predicate returns its length;
- otherwise, it returns nil. 'format-proper-list-p' is now an obsolete
- alias for the new function.
-
++Formerly, these functions often (though not always) silently returned
++nil. For example, if there is an access error, I/O error or low-level
+integer overflow when getting the attributes of a file F,
+'(file-attributes F)' now signals an error instead of returning nil.
+These functions still behave as before if the only problem is that the
+file does not exist. The affected primitives are
+'directory-files-and-attributes', 'file-acl', 'file-attributes',
+'file-modes', 'file-newer-than-file-p', 'file-selinux-context',
+'file-system-info', and 'set-visited-file-modtime'.
+
+---
+** The function 'eldoc-message' now accepts a single argument.
+Programs that called it with multiple arguments before should pass
+them through 'format' first. Even that is discouraged: for ElDoc
+support, you should set 'eldoc-documentation-function' instead of
+calling 'eldoc-message' directly.
+
++---
+** Old-style backquotes now generate an error.
+They have been generating warnings for a decade. To interpret
+old-style backquotes as new-style, bind the new variable
+'force-new-style-backquotes' to t.
+
++---
+** Defining a Common Lisp structure using 'cl-defstruct' or
+'cl-struct-define' whose name clashes with a builtin type (e.g.,
+'integer' or 'hash-table') now signals an error.
+
++---
+** When formatting a floating-point number as an octal or hexadecimal
+integer, Emacs now signals an error if the number is too large for the
+implementation to format.
+
+++++
+** 'logb' now returns infinity when given an infinite or zero argument,
+and returns a NaN when given a NaN. Formerly, it returned an extreme
+fixnum for such arguments.
+
+---
+** Some functions and variables obsolete since Emacs 22 have been removed:
+archive-mouse-extract, assoc-ignore-case, assoc-ignore-representation,
+backward-text-line, blink-cursor, bookmark-exit-hooks,
+c-opt-op-identitier-prefix, comint-use-prompt-regexp-instead-of-fields,
+compilation-finish-function, count-text-lines, cperl-vc-header-alist,
+custom-face-save-command, cvs-display-full-path, cvs-fileinfo->full-path,
+delete-frame-hook, derived-mode-class, describe-char-after, describe-project,
+desktop-basefilename, desktop-buffer-handlers, desktop-buffer-misc-functions,
+desktop-buffer-modes-to-save, desktop-enable, desktop-load-default,
+dired-omit-files-p, disabled-command-hook, dungeon-mode-map,
+electric-nroff-mode, electric-nroff-newline, electric-perl-terminator,
+focus-frame, forward-text-line, generic-define-mswindows-modes,
+generic-define-unix-modes, generic-font-lock-defaults, goto-address-at-mouse,
+highlight-changes-colours, ibuffer-elide-long-columns, ibuffer-hooks,
+ibuffer-mode-hooks, icalendar-convert-diary-to-ical,
+icalendar-extract-ical-from-buffer, imenu-always-use-completion-buffer-p,
+ipconfig-program, ipconfig-program-options, isearch-lazy-highlight-cleanup,
+isearch-lazy-highlight-initial-delay, isearch-lazy-highlight-interval,
+isearch-lazy-highlight-max-at-a-time, iswitchb-use-fonts,
+latin1-char-displayable-p, mouse-wheel-click-button, mouse-wheel-down-button,
+mouse-wheel-up-button, new-frame, pascal-outline, process-kill-without-query,
+recentf-menu-append-commands-p, rmail-pop-password,
+rmail-pop-password-required, savehist-load, set-default-font,
+spam-list-of-processors, speedbar-add-ignored-path-regexp,
+speedbar-buffers-line-path, speedbar-ignored-path-expressions,
+speedbar-ignored-path-regexp, speedbar-line-path, speedbar-path-line,
+timer-set-time-with-usecs, tooltip-gud-display, tooltip-gud-modes,
+tooltip-gud-toggle-dereference, unfocus-frame, unload-hook-features-list,
+update-autoloads-from-directories, vc-comment-ring, vc-comment-ring-index,
+vc-comment-search-forward, vc-comment-search-reverse, vc-comment-to-change-log,
+vc-diff-switches-list, vc-next-comment, vc-previous-comment, view-todo,
+x-lost-selection-hooks, x-sent-selection-hooks.
+
+---
+** Further functions and variables obsolete since Emacs 24 have been removed:
+default-directory-alist, dired-default-directory,
+dired-default-directory-alist, dired-enable-local-variables,
+dired-hack-local-variables, dired-local-variables-file, dired-omit-here-always.
+
+++++
+** Garbage collection no longer treats miscellaneous objects specially;
+they are now allocated like any other pseudovector. As a result, the
+'garbage-collect' and 'memory-use-count' functions no longer return a
+'misc' component, and the 'misc-objects-consed' variable has been
+removed.
+
++++
+** Reversed character ranges are no longer permitted in 'rx'.
+Previously, ranges where the starting character is greater than the
+ending character were silently omitted.
+For example, '(rx (any "@z-a" (?9 . ?0)))' would match '@' only.
+Now, such 'rx' expressions generate an error.
+
+---
+** Internal 'rx' functions and variables have been removed,
+as a consequence of an improved implementation. Packages using
+these should use the public 'rx' and 'rx-to-string' instead.
+'rx-constituents' is still available for compatibility, but the new
+extension mechanism is preferred: 'rx-define', 'rx-let' and
+'rx-let-eval'.
+
++++
+** 'text-mode' no longer sets the value of 'indent-line-function'.
+The global value of 'indent-line-function', which defaults to
+'indent-relative', will no longer be reset locally when turning on
+'text-mode'.
+
+To get back the old behavior, add a function to 'text-mode-hook' which
+performs '(setq-local indent-line-function #'indent-relative)'.
+
++---
+** 'make-process' no longer accepts a non-nil ':stop' key. This has
+never worked reliably, and now causes an error.
+
++++
+** 'eventp' no longer returns non-nil for lists whose car is nil.
+This is consistent with the fact that nil, though a symbol, is not a
+valid event type.
+
+---
+** The obsolete package xesam.el (since Emacs 24) has been removed.
+
++++
+** The XBM image handler now accepts a ':stride' argument, which should
+be specified in image specs representing the entire bitmap as a single
+bool vector.
+
++++
+** 'regexp-quote' may return its argument string.
+If the argument needs no quoting, it can be returned instead of a copy.
+
++++
+** Mouse scroll up and down with control key modifier changes font size.
+Previously, the control key modifier was used to scroll up or down by
+an amount which was close to near a full screen. This is now instead
+available by scrolling with the meta modifier key.
+
+To get the old behavior back, customize the user option
+'mouse-wheel-scroll-amount', or add the following to your init file:
+
+(customize-set-variable 'mouse-wheel-scroll-amount
+ '(5 ((shift) . 1) ((control) . nil)))
+
+By default, the font size will be changed in the window that the mouse
+pointer is over. To change this behavior, you can customize the user
+option 'mouse-wheel-follow-mouse'. Note that this will also affect
+scrolling.
+
+++++
+** Mouse scroll up and down with control key modifier also works on images
+where it scales the image under the mouse pointer.
+
+---
+** 'help-follow-symbol' now signals 'user-error' if point (or the
+position pointed to by the argument POS) is not in a symbol.
+
+\f
+* Lisp Changes in Emacs 27.1
+
- ** Making scroll bar and fringe settings persistent for windows.
++++
+** Emacs Lisp integers can now be of arbitrary size.
+Emacs uses the GNU Multiple Precision (GMP) library to support
+integers whose size is too large to support natively. The integers
+supported natively are known as "fixnums", while the larger ones are
+"bignums". The new predicates 'bignump' and 'fixnump' can be used to
+distinguish between these two types of integers.
+
+All the arithmetic, comparison, and logical (a.k.a. "bitwise")
+operations where bignums make sense now support both fixnums and
+bignums. However, note that unlike fixnums, bignums will not compare
+equal with 'eq', you must use 'eql' instead. (Numerical comparison
+with '=' works on both, of course.)
+
+Since large bignums consume a lot of memory, Emacs limits the size of
+the largest bignum a Lisp program is allowed to create. The
+nonnegative value of the new variable 'integer-width' specifies the
+maximum number of bits allowed in a bignum. Emacs signals an integer
+overflow error if this limit is exceeded.
+
+Several primitive functions formerly returned floats or lists of
+integers to represent integers that did not fit into fixnums. These
+functions now simply return integers instead. Affected functions
+include functions like 'encode-char' that compute code-points, functions
+like 'file-attributes' that compute file sizes and other attributes,
+functions like 'process-id' that compute process IDs, and functions like
+'user-uid' and 'group-gid' that compute user and group IDs.
+
++++
+** 'overflow-error' is now documented as a subcategory of 'range-error'.
+Formerly it was undocumented, and was (incorrectly) a subcategory
+of 'domain-error'.
+
+** Time values
+
++++
+*** New function 'time-convert' converts Lisp time values to Lisp
+timestamps of various forms, including a new timestamp form '(TICKS
+. HZ)' where TICKS is an integer and HZ a positive integer denoting a
+clock frequency.
+
++++
+*** Although the default timestamp format is still '(HI LO US PS)',
+it is planned to change in a future Emacs version, to exploit bignums.
+The documentation has been updated to mention that the timestamp
+format may change and that programs should use functions like
+'format-time-string', 'decode-time', and 'time-convert' rather than
+probing the innards of a timestamp directly, or creating a timestamp
+by hand.
+
++++
+*** Decoded (calendrical) timestamps now have subsecond resolution.
+This affects 'decode-time', which generates these timestamps, as well
+as functions like 'encode-time' that accept them. The subsecond info
+is present as a '(TICKS . HZ)' value in the seconds element of a
+decoded timestamp, and 'decode-time' has a new optional FORM argument
+specifying the form of the seconds member. For example, if X is the
+timestamp '(1566009571321878186 . 1000000000)', which represents
+"2019-08-17 02:39:31.321878186 UTC", '(decode-time X t t)' returns
+'((31321878186 . 1000000000) 39 2 17 8 2019 6 nil 0)' instead of the
+traditional '(31 39 2 17 8 2019 6 nil 0)' returned by plain
+'(decode-time X t)'. Although the default FORM is currently
+'integer', which truncates the seconds to an integer and is the
+traditional behavior, this default may change in future Emacs
+versions, so callers requiring an integer should specify FORM
+explicitly.
+
++++
+*** 'encode-time' supports a new API '(encode-time TIME)'.
+The old 'encode-time' API is still supported.
+
++++
+*** A new package to parse ISO 8601 time, date, durations and
+intervals has been added. The main function to use is
+'iso8601-parse', but there's also 'iso8601-parse-date',
+'iso8601-parse-time', 'iso8601-parse-duration' and
+'iso8601-parse-interval'. All these functions return decoded time
+structures, except the final one, which returns three of them (start,
+end and duration).
+
++++
+*** 'time-add', 'time-subtract', and 'time-less-p' now accept
+infinities and NaNs too, and propagate them or return nil like
+floating-point operators do. If both arguments are finite, these
+functions now return exact results instead of rounding in some cases,
+and they also avoid excess precision when that is easy.
+
++++
+*** New function 'time-equal-p' compares time values for equality.
+
++++
+*** 'format-time-string' supports a new conversion specifier flag '+'
+that acts like the '0' flag but also puts a '+' before nonnegative
+years containing more than four digits. This is for compatibility
+with POSIX.1-2017.
+
++++
+*** To access (or alter) the elements a decoded time value, the
+'decoded-time-second', 'decoded-time-minute', 'decoded-time-hour',
+'decoded-time-day', 'decoded-time-month', 'decoded-time-year',
+'decoded-time-weekday', 'decoded-time-dst' and 'decoded-time-zone'
+accessors can be used.
+
+*** The new functions 'date-days-in-month' (which will say how many
+days there are in a month in a specific year), 'date-ordinal-to-time'
+(that computes the date of an ordinal day), 'decoded-time-add' (for
+doing computations on a decoded time structure), 'make-decoded-time'
+(for making a decoded time structure with only the given keywords
+filled out), and 'encoded-time-set-defaults' (which fills in nil
+elements as if it's midnight January 1st, 1970) have been added.
+
+++++
++*** In the DST slot, 'encode-time' and 'parse-time-string' now return -1
++if it is not known whether daylight saving time is in effect.
++Formerly they were inconsistent: 'encode-time' returned t in this
++situation, whereas 'parse-time-string' returned nil. Now they
++consistently use use nil to mean that DST is not in effect, and use -1
++to mean that it is not known whether DST is in effect.
++
+++++
++** New macro 'benchmark-progn'.
++This macro works like 'progn', but messages how long it takes to
++evaluate the body forms. The value of the last form is the return
++value.
++
+++++
++** New function 'read-char-from-minibuffer'.
++This function works like 'read-char', but uses 'read-from-minibuffer'
++to read a character, so it maintains a history that can be navigated
++via usual minibuffer keystrokes 'M-p'/'M-n'.
++
++---
++** New variables 'set-message-function' and 'clear-message-function'
++can be used to specify functions to show and clear messages that
++normally are displayed in the echo area.
++
+++++
++** 'setq-local' can now set an arbitrary number of variables, which
++makes the syntax more like 'setq'.
++
++---
++** 'reveal-mode' can now also be used for more than to toggle between
++invisible and visible: It can also toggle 'display' properties in
++overlays. This is only done on 'display' properties that have the
++'reveal-toggle-invisible' property set.
++
+++++
++** 'process-contact' now takes an optional NO-BLOCK argument to allow
++not waiting for a process to be set up.
++
++---
++** New variable 'read-process-output-max' controls sub-process throughput.
++This variable determines how many bytes can be read from a sub-process
++in one read operation. The default, 4096 bytes, was previously a
++hard-coded constant. Setting it to a larger value might enhance
++throughput of reading from sub-processes that produces vast
++(megabytes) amounts of data in one go.
++
+++++
++** The new user option 'quit-window-hook' is now run first when
++executing the 'quit-window' command.
++
++** The user options 'help-enable-completion-auto-load',
++'help-enable-auto-load' and 'vhdl-project-auto-load', as well as the
++function 'vhdl-auto-load-project' have been renamed to have "autoload"
++without the hyphen in their names. Obsolete aliases from the old
++names have been added.
++
+++++
++** Buttons (created with 'make-button' and related functions) can
++now use the 'button-data' property. If present, the data in this
++property will be passed on to the 'action' function instead of the
++button itself in 'button-activate'.
++
+++++
++** 'defcustom' now takes a ':local' keyword that can be either t or
++'permanent', which mean that the variable should be automatically
++buffer-local. 'permanent' also sets the variable's 'permanent-local'
++property.
++
+++++
++** The new macro 'with-suppressed-warnings' can be used to suppress
++specific byte-compile warnings.
++
+++++
++** The new macro 'ignore-error' is like 'ignore-errors', but takes a
++specific error condition, and will only ignore that condition. (This
++can also be a list of conditions.)
++
++---
++** The new function 'byte-compile-info-message' can be used to output
++informational messages that look pleasing during the Emacs build.
++
++---
++** New 'help-fns-describe-variable-functions' hook.
++Makes it possible to add metadata information to 'describe-variable'.
++
++** i18n (internationalization)
++
++---
++*** ngettext can be used now to return the right plural form
++according to the given numeric value.
++
+++++
++** 'inhibit-null-byte-detection' is renamed to 'inhibit-nul-byte-detection'.
++
+++++
++** 'self-insert-command' takes the char to insert as (optional) argument.
++
+++++
++** 'lookup-key' can take a list of keymaps as argument.
++
+++++
++** 'condition-case' now accepts 't' to match any error symbol.
++
+++++
++** New function 'proper-list-p'.
++Given a proper list as argument, this predicate returns its length;
++otherwise, it returns nil. 'format-proper-list-p' is now an obsolete
++alias for the new function.
++
++---
+** 'define-minor-mode' automatically documents the meaning of ARG.
+
++++
+** The function 'recenter' now accepts an additional optional argument.
+By default, calling 'recenter' will not redraw the frame even if
+'recenter-redisplay' is non-nil. Call 'recenter' with the new second
+argument non-nil to force redisplay per 'recenter-redisplay's value.
+
++++
+** New functions 'major-mode-suspend' and 'major-mode-restore'.
+Use them when switching temporarily to another major mode, e.g. for
+'hexl-mode', or to switch between 'c-mode' and 'image-mode' in XPM.
+
++++
+** New macro 'dolist-with-progress-reporter'.
+This works like 'dolist', but reports progress similar to
+'dotimes-with-progress-reporter'.
+
++++
+** New hook 'after-delete-frame-functions'.
+This works like 'delete-frame-functions', but runs after the frame to
+be deleted has been made dead and removed from the frame list.
+
+---
+** The function 'provided-mode-derived-p' was extended to support aliases.
+The function now returns non-nil when the argument MODE is derived
+from any alias of any of MODES.
+
++++
+** New frame focus state inspection interface.
+The hooks 'focus-in-hook' and 'focus-out-hook' are now obsolete.
+Instead, attach to 'after-focus-change-function' using 'add-function'
+and inspect the focus state of each frame using 'frame-focus-state'.
+
++++
+** Emacs now requests and recognizes focus-change notifications from TTYs.
+On terminal emulators that support the feature, Emacs can now support
+'focus-in-hook' and 'focus-out-hook' for TTY frames.
+
++++
+** Window-specific face remapping.
+Face specifications (of the kind used in 'face-remapping-alist')
+now support filters, allowing faces to vary between different windows
+displaying the same buffer. See the node "(elisp) Face Remapping"
+of the Emacs Lisp Reference manual for more detail.
+
++++
+** Window change functions have been redesigned.
+Hooks reacting to window changes run now only when redisplay detects
+that a change has actually occurred. Six hooks are now provided:
+'window-buffer-change-functions' (run after window buffers have
+changed), 'window-size-change-functions' (run after a window was
+assigned a new buffer or size), 'window-configuration-change-hook'
+(like the former but run also when a window was deleted),
+'window-selection-change-functions' (run when the selected window
+changed) and 'window-state-change-functions' and
+'window-state-change-hook' (run when any of the preceding ones is
+run). Applications can enforce running the latter two using the new
+function 'set-frame-window-state-change'. 'window-scroll-functions'
+are unaffected by these changes.
+
+In addition, a number of functions now allow the caller to detect what
+has changed since last redisplay: 'window-old-buffer' returns for any
+window the buffer it showed at that time. ‘old-selected-window’ and
+'old-selected-frame' return the window and frame that were selected
+during last redisplay. 'window-old-pixel-width' (renamed from
+'window-pixel-width-before-size-change'), 'window-old-pixel-height'
+(renamed from 'window-pixel-height-before-size-change'),
+'window-old-body-pixel-width' and 'window-old-body-pixel-height'
+return the total and body sizes of any window during last redisplay.
+
+Also 'run-window-configuration-change-hook' is declared obsolete.
+
+See the section "(elisp) Window Hooks" in the Elisp manual for a
+detailed explanation of the new behavior.
+
++++
- +++
- ** In the DST slot, 'encode-time' and 'parse-time-string' now return -1
- if it is not known whether daylight saving time is in effect.
- Formerly they were inconsistent: 'encode-time' returned t in this
- situation, whereas 'parse-time-string' returned nil. Now they
- consistently use use nil to mean that DST is not in effect, and use -1
- to mean that it is not known whether DST is in effect.
-
++** Scroll bar and fringe settings can now be made persistent for windows.
+The functions 'set-window-scroll-bars' and 'set-window-fringes' now
+have a new optional argument that makes the settings they produce
+reliably survive subsequent invocations of 'set-window-buffer'.
+
++++
+** New user option 'resize-mini-frames'.
+This option allows to automatically resize minibuffer-only frames
+similarly to how minibuffer windows are resized on "normal" frames.
+
++++
+** New buffer display action function 'display-buffer-in-direction'.
+This function allows to specify the location of the window chosen by
+'display-buffer' in various ways.
+
++++
+** New buffer display action alist entry 'dedicated'.
+Such an entry allows to specify the dedicated status of a window
+created by 'display-buffer'.
+
++++
+** New buffer display action alist entry 'window-min-height'.
+Such an entry allows to specify a minimum height of the window used
+for displaying a buffer. 'display-buffer-below-selected' is the only
+action function to respect it at the moment.
+
++++
+** New buffer display action alist entry 'direction'.
+This entry is used to specify the location of the window chosen by
+'display-buffer-in-direction'.
+
++++
+** Additional meaning of display action alist entry 'window'.
+A 'window' entry can now also specify a reference window for
+'display-buffer-in-direction'.
+
++++
+** The function 'assoc-delete-all' now takes an optional predicate argument.
+
++++
+** New function 'string-distance' to calculate the Levenshtein distance
+between two strings.
+
+++++
+** 'print-quoted' now defaults to t, so if you want to see
+'(quote x)' instead of 'x you will have to bind it to nil where applicable.
+
++++
+** Numbers formatted via '%o' or '%x' are now formatted as signed integers.
+This avoids problems in calls like '(read (format "#x%x" -1))', and is
+more compatible with bignums. To get the traditional machine-dependent
+behavior, set the experimental variable 'binary-as-unsigned' to t,
+and if the new behavior breaks your code please email
+<32252@debbugs.gnu.org>. Because '%o' and '%x' can now format signed
+integers, they now support the '+' and space flags.
+
++++
+** In Emacs Lisp mode, symbols with confusable quotes are highlighted.
+For example, the first character in '‘foo' would be highlighted in
+'font-lock-warning-face'.
+
++++
+** Omitting variables after '&optional' and '&rest' is now allowed.
+For example '(defun foo (&optional))' is no longer an error. This is
+sometimes convenient when writing macros. See the ChangeLog entry
+titled "Allow '&rest' or '&optional' without following variable
+(Bug#29165)" for a full listing of which arglists are accepted across
+versions.
+
++---
+** Internal parsing commands now use 'syntax-ppss' and disregard
+'open-paren-in-column-0-is-defun-start'. This affects mostly things like
+'forward-comment', 'scan-sexps', and 'forward-sexp' when parsing backward.
+The new variable 'comment-use-syntax-ppss' can be set to nil to recover
+the old behavior if needed.
+
++---
+** The 'server-name' and 'server-socket-dir' variables are set when a
+socket has been passed to Emacs.
+
+---
+** The 'file-system-info' function is now available on all platforms.
+instead of just Microsoft platforms. This fixes a 'get-free-disk-space'
+bug on OS X 10.8 and later.
+
+---
+** The function 'get-free-disk-space' returns now a non-nil value for
+remote systems, which support this check.
+
++++
+** 'memory-limit' now returns a better estimate of memory consumption.
+
++++
+** When interpreting 'gc-cons-percentage', Emacs now estimates the
+heap size more often and (we hope) more accurately. E.g., formerly
+'(progn (let ((gc-cons-percentage 0.8)) BODY1) BODY2)' continued to use
+the 0.8 value during BODY2 until the next garbage collection, but that
+is no longer true. Applications may need to re-tune their GC tricks.
+
++++
+** New macro 'combine-change-calls' arranges to call the change hooks
+('before-change-functions' and 'after-change-functions') just once
+each around a sequence of lisp forms, given a region. This is
+useful when a function makes a possibly large number of repetitive
+changes and the change hooks are time consuming.
+
++++
+** 'eql', 'make-hash-table', etc. now treat NaNs consistently.
+Formerly, some of these functions ignored signs and significands of
+NaNs. Now, all these functions treat NaN signs and significands as
+significant. For example, '(eql 0.0e+NaN -0.0e+NaN)' now returns nil
+because the two NaNs have different signs; formerly it returned t.
+Also, Emacs now reads and prints NaN significands; e.g., if X is a
+NaN, '(format "%s" X)' now returns "0.0e+NaN", "1.0e+NaN", etc.,
+depending on X's significand.
+
++++
+** The function 'make-string' accepts an additional optional argument.
+If the optional third argument is non-nil, 'make-string' will produce
+a multibyte string even if its second argument is an ASCII character.
+
++---
+** '(format "%d" X)' no longer mishandles a floating-point number X that
+does not fit in a machine integer.
+
+---
+** New coding-system 'ibm038'.
+This is the International EBCDIC encoding, also available as aliases
+'ebcdic-int' and 'cp038'.
+
- +++
- ** Emacs now supports resizing and rotating images without ImageMagick.
- All modern systems support this feature. (On GNU and Unix systems,
- Cairo drawing or the XRender extension to X11 is required for this to
- be available; the configure script will test for it and, if found,
- enable scaling.)
-
- The new function 'image-transforms-p' can be used to test whether any
- given frame supports these capabilities.
-
++---
+** New JSON parsing and serialization functions 'json-serialize',
+'json-insert', 'json-parse-string', and 'json-parse-buffer'. These
+are implemented in C using the Jansson library.
+
++++
+** New function 'ring-resize'.
+'ring-resize' can be used to grow or shrink a ring.
+
++++
+** New function 'flatten-tree'.
+'flatten-list' is provided as an alias. These functions take a tree
+and 'flatten' it such that the result is a list of all the terminal
+nodes.
+
++++
+** 'zlib-decompress-region' can partially decompress corrupted data.
+If the new optional ALLOW-PARTIAL argument is passed, then the data
+that was decompressed successfully before failing will be inserted
+into the buffer.
+
+** Mailcap
+
+---
+*** The new function 'mailcap-file-name-to-mime-type' has been added.
+It's a simple convenience function for looking up MIME types based on
+file name extensions.
+
++---
+*** The default way the list of possible external viewers for MIME
+types is sorted and chosen has changed. Earlier, the most specific
+viewer was chosen, even if there was a general override in "~/.mailcap".
+For instance, if "/etc/mailcap" has an entry for "image/gif", that one
+will be chosen even if you have an entry for "image/*" in your
+"~/.mailcap" file. But with the new method, entries from "~/.mailcap"
+overrides all system and Emacs-provided defaults. To get the old
+method back, set 'mailcap-prefer-mailcap-viewers' to nil.
+
+** URL
+
++---
+*** The 'file:' handler no longer looks for "index.html" in
+directories if you ask it for a "file:///dir" URL. Since this is a
+low-level library, such decisions (if they are to be made at all) are
+left to higher-level functions.
+
+---
+** The url-ns.el library is now marked obsolete.
+This library is used to open configuration files for the long defunct
+web browser Netscape, and is no longer relevant.
+
+** Image mode
+
++---
+*** New library Exif.
+An Exif library has been added that can parse JPEG files and output
+data about creation times and orientation and the like.
+'exif-parse-file' and 'exif-parse-buffer' are the main interface
+functions.
+
++---
+*** 'image-mode' now uses this library to automatically rotate images
+according to the orientation in the Exif data, if any.
+
++---
+*** New library image-converter.
+If you need to view exotic image formats for which Emacs doesn't have
+native support, customize the new user option
+'image-use-external-converter' to t. If your system has
+GraphicsMagick, ImageMagick or 'ffmpeg' installed, they will then be
+used to convert images automatically before displaying them.
+
++---
+*** 'auto-mode-alist' now includes many of the types typically
+supported by the external image converters, like WEPB, BMP and ICO.
+These now default to using 'image-mode'.
+
++---
+*** 'imagemagick-types-inhibit' disables using ImageMagick by default.
+'image-mode' started using ImageMagick by default for all images
+some years back. It now respects 'imagemagick-types-inhibit' as a way
+to disable that.
+
+---
+*** Some 'image-mode' variables are now buffer-local.
+The image parameters 'image-transform-rotation',
+'image-transform-scale' and 'image-transform-resize' are now declared
+buffer-local, so each buffer could have its own values for these
+parameters.
+
++++
+*** Three new 'image-mode' commands have been added: 'm', which marks
+the file in the dired buffer(s) for the directory the file is in; 'u',
+which unmarks the file; and 'w', which pushes the current buffer's file
+name to the kill ring.
+
++++
+*** The command 'image-rotate' now accepts a prefix argument.
+With a prefix argument, 'image-rotate' now rotates the image at point
+90 degrees counter-clockwise, instead of the default clockwise.
+
+** Modules
+
++---
+*** The function 'load' now behaves correctly when loading modules.
+Specifically, it puts the module name into 'load-history', prints
+loading messages if requested, and protects against recursive loads.
+
+++++
+*** New module environment function 'process_input' to process user
+input while module code is running.
+
+++++
+*** New module environment functions 'make_time' and 'extract_time' to
+convert between timespec structures and Emacs Lisp time values.
+
+++++
+*** New module environment functions 'make_big_integer' and
+'extract_big_integer' to create and extract arbitrary-size integer
+values.
+
+++++
+*** emacs-module.h now defines a macro 'EMACS_MAJOR_VERSION' that expands
+to the major version of the latest Emacs supported by the header.
+
++++
+** The function 'read-variable' now uses its own history list.
+The history of variable names read by 'read-variable' is recorded in
+the new variable 'custom-variable-history'.
+
+---
+** The functions 'string-to-unibyte' and 'string-to-multibyte' are no
+longer declared obsolete. We have found that there are legitimate use
+cases for these functions, where there's no better alternative. We
+believe that the incorrect uses of these functions all but disappeared
+by now, so we are un-obsoleting them.
+
++++
+** New function 'group-name' returns a group name corresponding to GID.
+
++++
+** 'make-process' now takes a keyword argument ':file-handler'; if
+that is non-nil, it will look for a file name handler for the current
+buffer's 'default-directory' and invoke that file name handler to make
+the process. That way 'make-process' can start remote processes.
+
++++
+** '(locale-info 'paper)' now returns the paper size on systems that support it.
+This is currently supported on GNUish hosts and on modern versions of
+MS-Windows.
+
++++
+** The function 'regexp-opt' accepts an additional optional argument.
+By default, the regexp returned by 'regexp-opt' may match the strings
+in any order. If the new third argument is non-nil, the match is
+guaranteed to be performed in the order given, as if the strings were
+made into a regexp by joining them with '\|'.
+
++++
+** The function 'regexp-opt', when given an empty list of strings, now
+returns a regexp that never matches anything, which is an identity for
+this operation. Previously, the empty string was returned in this
+case.
+
+++++
+** New constant 'regexp-unmatchable' contains a never-matching regexp.
+It is a convenient and readable way to specify a regexp that should
+not match anything, and is as fast as any such regexp can be.
+
+++++
+** New functions to handle the URL variant of base-64 encoding.
+New functions 'base64url-encode-string' and 'base64url-encode-region'
+implement the url-variant of base-64 encoding as defined in RFC4648.
+
+The functions 'base64-decode-string' and 'base64-decode-region' now
+accept an optional argument to decode the URL variant of base-64
+encoding.
+
++++
+** The function 'file-size-human-readable' accepts more optional arguments.
+The new third argument is a string put between the number and unit; it
+defaults to the empty string. The new fourth argument is a string
+representing the unit to use; it defaults to "B" when the second
+argument is 'iec' and the empty string otherwise. We recomment a
+space or non-breaking space as third argument, and "B" as fourth
+argument, circumstances allowing.
+
++++
+** 'format-spec' has been expanded with several modifiers to allow
+greater flexibility when customizing variables. The modifiers include
+zero-padding, upper- and lower-casing, and limiting the length of the
+interpolated strings. The function has now also been documented in
+the Emacs Lisp manual.
+
++++
+** 'directory-files-recursively' can now take an optional PREDICATE
+parameter to control descending into subdirectories, and a
+FOLLOW-SYMLINK parameter to say that symbolic links that point to
+other directories should be followed.
+
++++
+** New function 'xor' returns the boolean exclusive-or of its args.
+The function was previously defined in array.el, but has been moved to
+subr.el so that it is available by default. It now always returns the
+non-nil argument when the other is nil. Several duplicates of 'xor'
+in other packages are now obsolete aliases of 'xor'.
+
++++
+** 'define-globalized-minor-mode' now takes BODY forms.
+
++++
+** New text property 'help-echo-inhibit-substitution'.
+Setting this on the first character of a help string disables
+conversions via 'substitute-command-keys'.
+
++++
+** 'undo' can be made to ignore the active region for a command
+by setting 'undo-inhibit-region' symbol property of that command to
+non-nil. This is used by 'mouse-drag-region' to make the effect
+easier to undo immediately afterwards.
+
+---
+** When called interactively, 'next-buffer' and 'previous-buffer' now
+signal 'user-error' if there is no buffer to switch to.
+
+\f
+* Changes in Emacs 27.1 on Non-Free Operating Systems
+
+---
+** Battery status is now supported in all Cygwin builds.
+Previously it was supported only in the Cygwin-w32 build.
+
+** Emacs now handles key combinations involving the macOS "command"
+and "option" modifier keys more correctly.
+
+** MacOS modifier key behavior is now more adjustable.
+The behavior of the macOS "Option", "Command", "Control" and
+"Function" keys can now be specified separately for use with
+ordinary keys, function keys and mouse clicks. This allows using them
+in their standard macOS way for composing characters.
+
+** The special handling of 'frame-title-format' on NS where setting it
+to 't' would enable the macOS proxy icon has been replaced with a
+separate variable, 'ns-use-proxy-icon'. 'frame-title-format' will now
+work as on other platforms.
+
+---
+** New primitive 'w32-read-registry'.
+This primitive lets Lisp programs access the MS-Windows Registry by
+retrieving values stored under a given key. It is intended to be used
+for supporting features such as XDG-like location of important files
+and directories.
+
++++
+** The default value of 'w32-pipe-read-delay' is now zero.
+This speeds up reading output from sub-processes that produce a lot of
+data.
+
+This variable may need to be non-zero only when running DOS programs
+as Emacs subprocesses, which by now is not supported on modern
+versions of MS-Windows. Set this variable to 50 if for some reason
+you need the old behavior (and please report such situations to Emacs
+developers).
+
+---
+** New variable 'w32-multibyte-code-page'.
+This variable holds the value of the multibyte code page used by the
+system. It is usually zero, which indicates that 'w32-ansi-code-page'
+is being used, except in Far Eastern locales. When this variable is
+non-zero, Emacs at startup sets 'locale-coding-system' to the
+corresponding encoding, instead of using 'w32-ansi-code-page'.
+
+---
+** The default value of 'inhibit-compacting-font-caches' is t on MS-Windows.
+Experience shows that compacting font caches causes more trouble on
+MS-Windows than it helps.
+
++++
+** Font lookup on MS-Windows was improved to support rare scripts.
+To activate the improvement, run the new function
+'w32-find-non-USB-fonts' once per Emacs session, or assign to the new
+variable 'w32-non-USB-fonts' the list of scripts and the corresponding
+fonts. See the documentation of this function and variable in the
+Emacs manual for more details.
+
++++
+** On NS the behavior of drag and drop can now be modified by use of
+modifier keys in line with Apples guidelines. This makes the drag and
+drop behavior more consistent, as previously the sending application
+was able to 'set' modifiers without the knowledge of the user.
+
+** On NS multicolor font display is enabled again since it is also
+implemented in Emacs on free operating systems via Cairo drawing.
+
+\f
+----------------------------------------------------------------------
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
+
+\f
+Local variables:
+coding: utf-8
+mode: outline
+paragraph-separate: "[ \f]*$"
+end:
projects / emacs.git / commitdiff