XeTeX 0.99999 (February 2018, for TeX Live 2018)

* Fix bug that could cause text after a \discretionary{...}{...}{...}
  line-break to be dropped.
* Avoid risk of generating broken UTF-8 in error context messages.
* Interpret optical size info in OpenType 'size' feature as "big
  points" units, rather than TeX points.
* Set a non-zero exit code if the pipe to the output driver returns
  an error.
* Correction for longstanding input_ln bug (stripping trailing tabs).
  (Karl Berry)
* Guard against out-of-range result from UTF-8 decoding, and return
  U+FFFD Replacement Character instead. (Akira Kakuto)
* Fix bugs involving \strcmp and \mdfivesum primitives. (Hironobu
  Yamashita)
* Fixes issue where \primitive\vrule\q incorrectly swallows the \q
  instead of giving an error. (Hironori Kitagawa)
* Properly close input pipes used in \input or \openin. (Hironobu
  Yamashita)
* Make \uchyph work with native fonts. (Hironobu Yamashita)
* Fixed bug in \ifprimitive. (Hironori Kitagawa)
* Support /Rotate in PDF image inclusion. (Akira Kakuto)
* If DPI info is missing in JPEG files, assume 72.0 to avoid
  division by zero. (Akira Kakuto)

==============================================================
XeTeX 0.99998 (April 22, 2016)

* Fixed long-standing bug that made \ifcat\span...\fi (and similar
  constructions with \cr, \crcr) behave incorrectly.
* Also fixed initialization of \delcode values for supplementary-
  plane characters.

==============================================================
XeTeX 0.99997 (March 2016, for TeX Live 2017)

* Unicode/OpenType math implementation now based on HarfBuzz's MATH
  table support, for easier ongoing maintenance.
* Minor bug fixes (revision history available at xetex.sf.net).

==============================================================
XeTeX 0.99996 (March 2016, for TeX Live 2016)

* Added \XeTeXhyphenatablelength primitive that sets the maximum
  length of word that XeTeX will attempt to hyphenate (default: 63).

==============================================================
XeTeX 0.99995 (targeting TeX Live 2016)

* Added \XeTeXgenerateactualtext primitive to record original Unicode
  text in /ActualText annotations.
* Bumped the DVI id byte to 7, as this uses a new opcode that requires
  support in the driver.

==============================================================
XeTeX 0.99994 (unreleased experimental version)

* Increased character class limit to 4096.
* Added \XeTeXinterwordspaceshaping primitive, for contextual
  measurement (when set to 1) or full glyph shaping (when set to 2) of
  interword space with smart-enough fonts.

==============================================================
XeTeX 0.99993 (July 2015)

* Added \mdfivesum primitive
* Removed -q from the default xdvipdfmx output-driver command line
  (reverted 20160209, r39630 in TeX Live).

==============================================================
XeTeX 0.99992 was released 20150507 (in TeX Live 2015)

* New \Uchar and \Ucharcat primitives
* Fix various issues with UTF-16 and characters >= U+10000.
* Various image handling fixes by Akira Kakuto.
* Fix off-by-one error in display of \every... token registers, thanks to Bruno
  Le Floch.
* The XDV opcodes have been simplified slightly. The DVI id have been bumped to
  6 to reflect this.
* XeTeX now looks for the xdvipdfmx binary installed next to it and no longer
  requires that it is installed in the system PATH (this was previously done
  only on Windows).

==============================================================
XeTeX 0.99991 was released 20140614

* Drop build date from “--version” output.
* Drop Mac-specific image loading code, as it makes little sense after we
  dropped xdv2pdf. Supported image formats are the same on all platforms now.
* Fix OpenType math cut-ins support which was not always working properly.
* Avoid Unicode compatibility decomposition fallback for characters not
  supported by the font as it often result in loss of essential characteristics
  (like using regular Latin characters in place of missing math fraktur ones).
  Non compatibility decomposition and composition fallback is still supported.
* For hybrid OpenType/Graphite fonts, we now prefer using OpenType for
  compatibility with pre-0.9999 XeTeX.
* Fix many memory leaks when using AAT fonts on Mac.
* The “language” font option when loading Graphite fonts in now treated as a
  BCP 47 language tag not and OpenType one.
* Various Unicode fixes for Windows console (thanks to TANAKA Takuji).
* Respect vertical glyph positioning with AAT fonts (fixes, for example,
  rendering of the new Arabic fonts in Mac OS X 10.9).

==============================================================
XeTeX 0.9999.3 was released 20130528

* Fix bug with extensible accents resulting in invalid glyph id some times.
* Fix alternate index in multiple alternates features to be start from zero
  like pre-0.9999 XeTeX.
* Document multiple alternates syntax in the reference documentation.

==============================================================
XeTeX 0.9999.2 was released 20130406

* Fix regression in \XeTeXOT* primitives with fonts where the number of
  languages in a given script is not the same in both GSUB and GPOS tables.

* Add a workaround for a bug in clang headers to allow building with it on Mac.

* Fix regression in loading PNG files on Mac.

* Fix multiple regression with vertical text layout.

* Update to HarfBuzz 0.9.15 fixing a couple of regressions with Arabic non
  spacing marks and Hangul jamo.

* Various build fixes for third party libraries.

* XeTeX reference is now included in the release tarball.

xdvipdfmx:
* Speed up inclusion of eps figures by Tsuchimura Nobuyuki.

==============================================================
XeTeX 0.9999.1 was released 20130322

* Fix loading font files on PPC Mac OS 10.5 (and potentially other versions of
  Mac).

* Fix handling of ‘script’ and ‘language’ font options to be treated again as
  OpenType not ISO tags, so that passing version 2 Indic script tags works
  (though this is generally not needed as HarfBuzz will always use version 2
  shaping if the font has it, regardless of the tag used).

* Fix loading JPEG images that do not specify a resolution.

* When printing multi-byte characters to log or terminal avoid inserting new
  lines in the middle of the characters, and count the characters not the bytes
  when calculating line length.

* Update to HarfBuzz 0.9.14, a couple of Indic and Hangul shaping bugs.

xdvipdfmx:
* Speed up calculating glyph widths in native font.

* Don’t crash when /tmp is full.

==============================================================
XeTeX 0.9999.0 was released 20130311

* Port OpenType layout from ICU LayoutEngine to HarfBuzz.
  HarfBuzz is actively maintained and generally have much wider support for
  OpenType spec, the switch fixes a number of OpenType bugs:
  - Support version 2 OpenType Indic specs.
  - Many other Indic OpenType bugs, and support for the latest additions to
    OpenType spec.
  - Incorrect application of contextual features.
  - Incorrect kerning in fonts that has both old “kern” table and new GPOS
    “kern” feature.
  - Allow suppressing Latin ligatures with ZWNJ.
  - Support for variation selectors.
  - Support for user-specified features with complex scripts.

* Port Graphite layout to from SilGraphite to HarfBuzz and Graphite2. Which
  provides a more robust Graphite support and also fixes a number of Graphite
  bugs.

* Port AAT font layout and font searching on Mac from the deprecated ATS/ATSUI
  to Core Text, and image support on Mac from QuickTime to ImageIO framework.
  XeTeX can be finally built on 64-bit Mac! Work contributed by Jiang Jiang.

* Add “/OT” font variant, similar to “/ICU” which is now deprecated.

* Add a “shaper” font option to specify HarfBuzz shapers (for testing).

* Guess script from input string if no one is given in the font definition,
  instead of defaulting to Latin.

* Support 4-letter tags for Graphite features.

* Fix applying negative delta glyph advance to the last glyph in the run, fixes
  issues with “halt” and “vhal” features.

* Use \U prefix for extended math primitives, allowing XeTeX and LuaTeX to use
  the same names for Unicode math primitives supported by both engines. The old
  \XeTeX* primitives have been deprecated and will be removed in the future.

* Support OpenType math cut ins.

* Fix “\show” and “\meaning” of “\Umathchar” to a print a form that is legal
  input.

* Fix italic correction to not depend on space factor being zero for OpenType
  fonts.

* Fix sporadic shifting of extensible accents.

* Fix typesetting XeTeX’s WEB code, in addition to various slight improvements.

* Prefer TrueType/OpenType over Type1 fonts with the same font name.

* Support input pipes, in line with other engines.

* Drop support for using “()” as font names quotes since it was causing file
  names with parenthesis not to be found.

* Fix “\show” with characters outside BMP.

* Print the actual character instead of hex code for characters outside BMP
  with “\show”, “\meaning”, “\showlists” and missing char log messages.

* Fix letterspacing if zero width glyphs.

* Try to get cap and x height from OS/2 table first.

* Reject bitmap only fonts.

* Include build date in “--version” output.

==============================================================
XeTeX 0.9998 was released 20120708

* Fix mismatch between fonts loaded by XeTeX and xdvipdfmx when multiple
  versions of the font exist.

* Fix “\the\textfont” with families > 15

* Extend “\fam” to accept family number up to 255.

* Fix build on Mac OS 10.7

OpenType math:

* Fix displacement of big operator's limits when “DisplayOperatorMinHeight” is
  higher than the size of the big operator.

* Fix too wide accents over accentees that has sub/superscript.

* Support extensible accents for “\overbrace” etc.

* Always take math constants from current font, fixes multiple math discrepancies.

* Honor relevant math constants when positioning sub/superscripts.

* Honor “AccentBaseHeight” when placing accents.

* Support “fixed” and “bottom” keywords in “\XeTeXmathaccent” for non growing
  and bottom accents, respectively.

* Fix horizontal placement of of accents over single letters to honor their top
  accent position value.

* Fix vertical placement of sub/superscripts of single letters to not be
  treated as non-single letters.

* Support proper positioning of nested accents.
