Today we are entering the public beta phase of MathJax v2.5. This release focused on improving rendering speed and MathML support.

The 2.5 release improves the speed of the HTML-CSS output by 30-40% (depending on content complexity, with higher gains in more complex situations) and introduces a new preview output (CommonHTML) which currently provides a rougher layout but is ~10x faster than the HTML-CSS output; in the long run, the CommomHTML output will reach the quality of the HTML-CSS and SVG outputs.

In terms of MathML support, Content MathML is now fully supported via a new extension and we have improved the experimental support for elementary math elements (with special thanks to contributions from David Carlisle). The 2.5 release also includes over 70 bug fixes to increase the quality and stability of MathJax (see below for details).

The beta is available via our CDN at beta.mathjax.org/mathjax/latest/MathJax.js which you can load it in place of the version you are currently using. Alternatively, you can get a ZIP archive or access the branch on GitHub.

**Note:** If you are using a pre-defined configuration, please note the new fast-preview mode is activated in these. If you want to de-activate it on your page, add the following to your page **before** `MathJax.js`

is loaded.

```
<script type="text/javascript">
window.MathJax = {
menuSettings: {CHTMLpreview: false}
};
</script>
```

As a user, you can deactivate the Fast Preview via the MathJax menu. Righ/Cmd-click any equation and go to `Math Settings -> Math Renderer -> Fast Preview`

.

**Remember that this is still beta software**, so if you are not an experienced user, you may want to wait for the official 2.5 release. We do not recommend that you use the 2.5-beta version for production environments, but do encourage you to test your content with it.

If you are linking to http://cdn.mathjax.org/mathjax/latest/MathJax.js, note that at the point of the official release of v2.5, the address will begin to serve MathJax v2.5. You can also continue to use v2.4 by linking to http://cdn.mathjax.org/mathjax/2.4-latest/MathJax.js instead — and you can change to that version at any point (it is available now). Once the official v2.5 release is made, the v2.5-beta address will be removed from the CDN.

The official release of v2.5 should occur within the next three weeks, but we want you to be able to start to test out the v2.5 features now. Please report any bugs you find to the issue tracker at https://github.com/mathjax/MathJax/issues.

Thanks for your continuing interest in MathJax. We hope that this release makes your MathJax experience even better.

The MathJax Team.

## 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. See our documentation for loading the extension.*Improved elementary math support*The experimental support for elementary math elements has been significantly improved special thanks to David Carlisle. It now ships in a separate extension`mml3.js</code>.`*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.

### Interface

- #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.

## Line-breaking

- #949 Fix processing error due to empty elements.

### HTML-CSS/SVG/nativeMML display

- #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.
- #975 Fix preview not clearing with CHTML-preview extension.
- #970 Fix moveable limits for inline operators in
`CommonHTML`output.

### TeX emulation

- #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.

### Asciimath

- #851 Prevent leading space in quote from causing processing errors.
- #431 Fix handling of special characters in exponents.
- #741 Add underbrace macro.

### MathML Handling

- #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 conversion to be customized.

### Fonts

### Localization

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

### APIs

## Misc

- #872 Add small delay between input and output phase to prevent performance degredation.