What’s New in MathJax v2.5

MathJax v2.5 includes a number of new features, as well a more than 70 important bug fixes. The following are some of the highlights.

Features

Speed improvements. The HTML-CSS output performance was improved by 30-40% (depending on content complexity, with higher gains in more complex content such as very long documents).
New output for fast preview. The new CommonHTML output provides a rough but 10x-faster rendering. The CHTML-preview extension will use this fast output as a preview mode for HTML-CSS or SVG output.
Improved Content MathML support. Content MathML is now fully supported via a new extension, in particular this allows customization of the conversion process.
Improved elementary math support The experimental support for elementary math elements has been significantly improved special thanks to David Carlisle.
NodeJS compatibility. Enable the implementation of a NodeJS API (released as MathJax-node).

Numerous display bugs, line-breaking problems, and interface issues have been resolved; for a detailed listing please check the release milestone.

#834 Fix incorrect line-width when zooming which can cause line-breaking problems.
#918 Fix zoom box size in NativeMML output.
#835 Fix zoom for equations extending beyond their bounding box.
#893 Fix outdated ARIA values for HTML-CSS and SVG output.
#860, #502 Preserve RDFa, microdata, aria labels, and other attributes in HTML-CSS and SVG output.
#935 Escape special characters in TeX annotations.
#912 Fix missing mstyle attributes in toMathML output.
#971 Fix lost attributes when toMathML is restarted.

#863 Fix broken MathML preview in MathML pre-processor.
#891 Fix deprecated regexp affecting mtable alignment.
#323 Improve MathPlayer compatibility on Internet Explorer 10+.
#826 Scale content in fallback fonts.
#898 Fix invalid SVG output when using fallback characters.
#800 Fix misplaced background color for stretched mphantom elements in SVG output.
#490 Fix \overline issues in combination with text-style limits.
#829 Implement \delimitershortfall, \delimiterfactor.
#775 Fix lost text content in SVG output.
#917 Fix cases of incorrect bounding boxes in HTML-CSS output.
#807 Fix clipping of table columns in HTML-CSS output.
#804 Fix cases of uneven subscripts.
#944 Fix rendering error when scaling-all-math of labeled equations.
#930 Fix SVG output failure when <math> element has inline styles with border or padding.
#931 Fix baseline alignment in Safari 6.2/7.1/8.0.
#937 Fix incorrect width in MathJax font data affecting underlining.
#966 Fix SVG output overlapping when using prefix notation.
#993 Add workaround for Native MathML in Gecko to re-enable mlabeledtr etc.
#1002 Enable SVG output to inherit surrounding text color.

#881 Allow \newenvironment to process optional parameters.
#889 remove extra space around some parenthesis constructs.
#856 Recognize comma as decimal delimiter in units.
#877 Fix bug related to multiple accent having different width.
#832 Fix multline environment not being centered in HTML-CSS output.
#776 Fix stretchy delimiters of binom and choose.
#900 Fix \buildrel getting TeX class ORD instead of REL.
#890 Enable px as dimension in \\[...].
#901 Allow \limits in more cases and add errors for some cases of multiple subscripts.
#903 Allow \hfill to set alignment in matrices and arrays (for old fashioned TeX layout).
#902 Convert \eqalignno and \leqalignno into mlabeledtr.
#906 Allow comma separated parameters in \mmlToken.
#913 Allow attributes in \mmlToken whose defaults are false or blank.
#972 Fix autoload of the color extension.
#375 Add \{, \}, and \\ to macros working within \text{} etc.
#969 Fix incorrect spacing with some \frac constructs.
#982 Fix incorrect spacing in aligned environments.
#1013 Fix processing error caused by ' in commutative diagrams using AMScd.js.
#1005 Add wikipedia-texvc.js extension.

#847 Fix line-breaks in annotation elements.
#805 Prevent empty annotation elements from causing math processing errors.
#769 Update indentshift implementation to meet clarified MathML specification.
#768 Fix processing of percentage values for indenshift.
#839 Update inheritance of displaystyle in mtable to meet clarified MathML specification.
#695 Allow Content MathML converion to be customized.
#964 Move experimental support for elementary math and RTL to its own extension.

#979 Updated locales thanks to Translatewiki.net; activate locales for Scots and Southern Balochi.

#870 Add Composer package information.
#872 Add small delay between input and output phase to prevent performance degredation.
#1016 Fix bug related to <script> elements with namespace prefix, e.g., in xHTML.