!Important Changes in LyX 2.4.0


!!Interface changes

* It is now possible to cancel background export processes at any time. A menu
  entry to do so will appear on the Document menu when such a process is
  underway.  The LFUN for this is export-cancel. One can also click on the red
  'x' next to the spinner to cancel export. Thanks to this functionality, we now
  remove the "Stop command?" prompt, which polled users whether to stop a long
  process.

* The items on the Edit menu have been reordered, and many of the shortcuts
  have been changed so that they are more intuitive in the case of often
  used items. We understand that this may frustrate some users and apologize,
  while noting that menu shortcuts can always be customized by copying the
  stdmenus.inc file to the user directory and editing it.

* Backspace and other forms of deletion will now merge paragraphs even when they 
  have different layouts.

* Ctrl-click on a cross-reference will now take you to its label.

* Default shortcuts for saving bookmarks have been changed to Alt-NUM, where
  NUM is the number of the bookmark. (They were previously Shift-F1, etc.)

* Shift-F3 can be used for word-find-backwards (i.e., find previous) on Linux
  and Windows.

* The shortcut to use the selection for a find on macOS is now Cmd-E, as is the
  Apple standard.  The shortcut for find the next occurrence of the current
  find buffer text is Cmd-G.  The shortcut for toggle of font emphasis has been
  changed to Cmd-Ctrl-E.

* Continuous spellcheck is now on by default, but only if the user does not have
  an existing preferences file. In that case, the old setting is preserved.

* Document (or selection statistics) is now shown in status bar and can be
  disabled by the context menu.

* The actual enabled state of the synchronize TeX output option of the document
  is used to enable or disable the menu item for forward-search.

* When using the document compare function, there is now an option to display the
  differences using a special "Document Compare" author.

* InsetRef now supports starred commands. The starred commands stop hyperref from
  creating a link (and are only available when hyperref is used). There is a 
  checkbox "No Hyperlink" for this purpose.

* Alt-Escape can be used to 'float' and redock widgets like the table of contents
  or source view.

!!Documents compilation process and images conversion

* LyX now uses utf8 encoding per default for all languages. This does
  not affect existing documents. Note that LyX also does not touch
  personal defaults and templates. That is to say, if you still see
  traditional encoding preset for new documents, you can change that
  by selecting "Unicode (utf8) [default]" and hitting "Save as
  Documents Defaults" afterwards. Your personal templates need to be
  changed manually if desired.

* LyX defaults to the "HE8" LaTeX font encoding with Hebrew if the
  "Culmus" LaTeX fonts are installed.

* Documents that use TeX fonts can only be compiled with XeTeX if the input
  encoding is set to "utf8-plain" or "ascii".

* With LyXHTML output, there are now different CSS classes generated for
  different depths: enumi, enumii, enumiii, and enumiv, and similarly for
  itemize: lyxitemi, etc. There is also a new HTMLClass tag, which makes it
  easier to provide specific classes for paragraphs.

* HTML support has been updated to output XHTML5 files. A major change is the
  use of XML entities instead of HTML ones (e.g., LyX now outputs -
  instead of ").

* DocBook support has been revamped and now targets DocBook 5 (i.e.
  only XML, SGML is gone). Some supporting files for the previous
  implementation have been removed: all examples (lib/examples),
  some layouts (existing documents should still work, but with a
  DocBook 5 output instead of DocBook 4 SGML). The dependency on
  sgmltools has been removed, this new support is always enabled.
  Having sgmltools installed or not will not change anything in LyX.

* Postscript -> PDF convertor (ps2pdf) uses -dALLOWPSTRANSPARENCY by
  default now (implemented since ghostscript 9.53.3, see bug #12303).

* There is a widespread ban on postscript conversions across different
  linux distributions and there are currently two way how to address
  various image conversion errors when typesetting your documents: 
  - either manually remove the bans of EPS/PDF coders in ImageMagick
    policy.xml configuration file
  - or install alternative converters for bitmap <-> postscript.
    In particular pdftoppm (poppler-utils) and tiff2ps (libtiff-tools)
    are now recognized and activated in case LyX detects ImageMagick
    policy ban. These will allow eps<->png(jpg) conversion chain to
    be found when processing your documents. 
  Package maintainers of distributions (e.g. openSUSE or Debian derivates)
  where ghostscript conversions of ImageMagick are banned can simply 
  add dependencies for poppler-utils and libtiff-tools to workaround
  the problem.


!!!The following pref variables were added in 2.4:

* \ct_additions_underlined true|false: determines whether additions in change tracking
  are underlined in the workarea (default: true).

* \ct_markup_copied true|false: determines whether change tracking markup should be
  preserved on copy/paste (default: false).

* \citation_search_view lyxpaperview: determines whether external script "lyxpaperview"
  should be used for looking up citation source.

* \draw_strategy partial|backingstore: when this is set to
  "backingstore", the drawing code will force the use of an
  intermediate surface, instead of just drawing changed regions on
  screen. Note that "backingstore" is actually always enforced on
  macOS and Wayland (default: partial).

* \screen_limit true|false: determines whether the text width on screen is limited
  (both fullscreen and normal view).

* \screen_width <length>: sets the width of the text on screen if \screen_limit is true.

!!!The following pref variables were changed in 2.4:



!!!The following pref variables are obsoleted in 2.4:

* \font_encoding
  The font encoding is now automatically set depending on the document
  fonts and languages.

* \fullscreen_limit
  Removed in favor of \screen_limit

* \fullscreen_width
  Removed in favor of \screen_width

* \use_qimage
  This is no longer necessary due to the rewrite of the painter.

* \use_pixmap_cacheqimage
  There is no evidence that this painting mode was useful anymore.

* \date_insert_format
  The function date-insert has been removed and superseded by info-insert date.
  The latter does not need a pref value anymore.


!!!The following new LyX functions have been introduced in 2.4:

* bibtex-database-list: output a list of all bibtex files used in the current buffer.
  The function outputs absolute paths in the OS style and separated by the os-specific
  path separator. This function is intended for bibliography managers.

* branch-sync-all: Open/close all insets of selected branch (depending on its activation status).

* buffer-reset-export advises LyX to remove the auxiliary files before doing the next
  export.

* buffer-write-as-template is a new convenience function to ease saving a document
  in the (personal) templates folder.

* export-cancel: Used to cancel background export processes.

* font-nospellcheck marks the word under cursor or selection to the effect that the
  spellchecker ignores it.

* ifrelatives is a helper function to check whether a buffer has a master or children.

* lyxfiles-open opens the new examples or templates dialog.

* master-buffer-forall executes an lfun in the master and all children of a document.

* paragraph-select is a new convenience function to select the paragraph
  surrounding the actual cursor position.

* search-string-set [arg] stores the <arg>, the currently selected text or the word under
  cursor in the search cache that is used by word-find[-backward|-forward] if no argument
  is given to those.

* spelling-add-local adds words for a given language to the document's local spelling
  dictionary.

* spelling-remove-local removes words for a given language from the document's local
  spelling dictionary.

* index-tag-all adds a copy of the index entry under cursor to after all occurrences of the
  word that precedes the index inset.

* inset-insert-copy inserts the inset's content (in ToC pane) at the position of the cursor.

* inset-split is a new convenience function that splits an inset into two at the given
  cursor position. This is only implemented for text insets currently.

* tabular-style-insert: Insert a table in a specified style.

* tab-group-next, tab-group-previous: Activate another tab group in split view.
  The new functions bound to F6/S-F6 in CUA bindings.


!!!The following LyX functions have been changed in 2.4:

* citation-insert now returns a list of undefined citations if passed through the LyX Server.

* file-insert: optional second parameter "ignorelang" to make the insertion
  ignore the inserted file's main language (and rather adapt it to the insertion
  context's language).

* info-insert buffer vcs-*: renamed to info-insert vcs *

* inset-edit recognizes optional argument "nogui" - no editor will be launched in
  such case, only filename will be returned (for use in scripts).

* outline-in/out can now take argument "local", that restricts their
  action to the current paragraph.

* set-graphics-group was renamed to graphics-set-group.

* tabular-feature: added toggle parameters "toggle-all-lines", "toggle-border-lines"
  and "toggle-inner-lines"

* word-delete-forward, word-delete-backward, char-delete-forward,
  char-delete-backward

  The 2.4 behavior of these functions is almost equivalent to the
  pre-2.3 behavior: without argument, it just deletes the
  next/previous element; with the "confirm" argument however, big
  insets are selected on the first call and deleted only on the
  second. This new behavior allow scripts to work intuitively and
  require the argument only for interactive use.


!!!The following LyX functions have been removed in 2.4:

* date-insert: obsoleted by info-insert date.

!!!The following LyX function has been added and then removed in 2.4 development cycle.

* bidi: used as a first solution to provide icons that change
  direction with language.


!!!The following LyX documents have been moved in 2.4:

* As a result of a major restructuring of the templates and example
  directories, almost all examples and templates files have been renamed and
  moved to subfolders that reflect the layout category.
  The files now have much more decriptive (and longer) names, and they use
  URL encoding for specific special characters such as '(', ')' and '&'.
  Notably also the file that opens for new users has been renamed (from
  splash.lyx to Welcome.lyx).


!!!The following new folders have been added to the LyX directory

* The examples and templates directories have been completely re-organized.
  They are now much more structured (by means of layout categories) and thus
  consist of many new subfolders.



!!!The following preferences files have been removed from the tarball in 2.4:



!!!The following metadata files have been added to the tarball in 2.4:

* Metainfo was updated from appdata.xml to org.lyx.LyX.metainfo.xml
  and is by default installed to /usr/share/metainfo/ per freedesktop.org
  recommendation.


!!Changes with respect to external programs and libraries in 2.4:

* The Qt5 libraries are now used by default. In order to link against
  Qt6 the configure option --enable-qt6 has to be used. Qt4 is not 
  supported anymore.

* The dependency on pplatex/dvipost was dropped.

* The dependency on sgmltools was dropped, see DocBook 5 section.

!!! Dependencies to generate ePub files:

* The DocBook XSLT 1.0 style sheets are a required dependency to generate
  ePub files. All versions since 1.76.0 are supported.

  Version 1.79.2 is bundled with LyX. If your system already provides xslt
  style sheets you can use configure parameter --without-xslt-stylesheets to
  avoid installing them.


* XSLT processor is needed, two options were successfully tested
  a) xsltproc
     - Works on Linux and OSX (tested with xsltproc 1.1.32).
     - Fails on Windows.
  b) Saxon
     - Tested on Linux, OSX and Windows.
     - Java is a required dependency. Any JVM for Java 1.4 should be supported.
     - Only Saxon versions 6.5.4 and 6.5.5 are supported.
     - Version 6.5.5 is bundled with LyX. If your system already provides Saxon
       (or xsltproc) you can use configure parameter --without-saxon to avoid
       installation of this library.

* bash_completion script was updated for a newer syntax.


!!Known issues in version 2.4.0

* See http://www.lyx.org/trac/wiki/BugTrackerHome


!!Caveats when upgrading from earlier versions to 2.4.x

* LyX now uses the parskip package for vertical paragraph separation. Since the
  output differs from the previous (sub-optimal) approach which applied paragraph
  separation to sections, lists etc. as well, existing documents
  are converted to use preamble code that maintains the previous layout.
  The downside is that the workarea looks as if paragraph indendation rather
  than paragraph separation was used (output is correct). We encourage you
  to try if the new layout suits you, remove the respective preamble code
  and re-set the paragraph separation to use the new layout.

* Autotools monolithic build option for building LyX binaries was removed,
  for compilation speedup use parallel building on multiple cores instead.

* Several ttf fonts (esint10.ttf, stmary10.ttf, wasy10.ttf) were changed
  to reflect the fact that newer Qt libraries do not support displaying certain
  codepoints anymore (bug #8493, #10161).
  Distribution packagers need to repack those font files in case they are
  delivering the fonts as a separated package dependent from core LyX
  in order to display correctly math symbols like \oint.

  Also note, that while it is still possible to compile LyX against Qt 4
  these math symbols will not be displayed correctly anymore on Qt 4.

!! If upgrading from a LyX version before 2.3.0

* Please additionally see the release notes from the versions in-between:
  https://wiki.lyx.org/LyX/ReleaseNotes


!!Detailed list of 2.4 changes

* For more comprehensive list of changes and new features in LyX 2.4 see
  https://wiki.lyx.org/LyX/NewInLyX24