---
id: migration
title: Migration Guide
---

## v0.15.0

`\relax` is now implemented as a function. It'll stop expansions and parsing,
so the behavior around `\relax` may change. For example, `\kern2\relax em` will
no longer work.

## v0.14.0

With module loaders that support conditional exports and ECMAScript modules,
`import katex from 'katex';` will import the ECMAScript module.

You can now use:
|Before                                    |After                             |
|------------------------------------------|----------------------------------|
|`require('katex/dist/contrib/[name].js')` | `require('katex/contrib/[name]')`|
|`import katex from 'katex/dist/katex.mjs'`| `import katex from 'katex'`      |
|`import 'katex/dist/contrib/[name].mjs'`  | `import 'katex/contrib/[name]'`  |

## v0.13.0

### Macro arguments
Tokens will not be expanded while parsing a macro argument. For example, `\frac\foo\foo`,
where the `\foo` is defined as `12`, will be parsed as `\frac{12}{12}`, not
`\frac{1}{2}12`. To expand the argument before parsing, `\expandafter` can
be used like `\expandafter\frac\foo\foo`.

### `\def`
`\def` no longer accepts a control sequence enclosed in braces. For example,
`\def{\foo}{}` no longer works and should be changed to `\def\foo{}`.

It also no longer accepts replacement text not enclosed in braces. For example,
`\def\foo1` no longer works and should be changed to `\def\foo{1}`.

### `\newline` and `\cr`
`\newline` and `\cr` no longer takes an optional size argument. To specify vertical
spacing, `\\` should be used.

### `\cfrac`, `\color`, `\textcolor`, `\colorbox`, `\fcolorbox`
They are no longer allowed as an argument to primitive commands, such as `\sqrt`
(without the optional argument) and super/subscript. For example,
`\sqrt\textcolor{red}{x}` no longer works and should be changed to
`\sqrt{\textcolor{red}{x}}`.