npm / katex

katex

What changed in katex 0.16 to 0.19, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-18.

3 breaking2 security4 new APIs and options1 performance4 behavior and defaults1 tooling26 fixes and other

See which of these apply to your code, ranked, in your agent:

npx @unstale/cli init

katex 0.192 changes

Missing character metrics are reported through strict with error code symbolNotInFont; warning formatting changes, strict callbacks are called, and strict: "error" mode produces errors.
0.19.0release notes

Strict callbacks returning undefined or null now warn instead of ignoring the issue; return false or "ignore" to suppress warnings.
0.19.0release notes

CSS classes are prefixed; users with custom styles or allowlists targeting KaTeX's internal classes must update their selectors.
0.18.0release notes

KaTeX: Existing prototype pollution can bypass trust restrictions
0.18.2security advisory
Prevents prototype pollution through settings.
0.18.2release notes

The strict option now handles character metrics warnings.
0.18.11release notes
KaTeX now falls back to the browser math font before Times New Roman.
0.18.10release notes

Type declarations were added for contrib modules, improving TypeScript support when using them.
0.18.9release notes

Trailing rows in align are now preserved.
0.18.8release notes
Preserves tags on empty final rows in array environments.
0.18.6release notes
Accepts U+10FFFF.
0.18.5release notes
Invalid environment names are now reported as ParseError, allowing callers to handle them as parse errors.
0.18.4release notes
Delimsizing now allows braced arguments.
0.18.3release notes
\htmlData now allows escaped commas in its input.
0.18.1release notes

The internal API changed; properties should no longer be wrapped in props.
0.17.0release notes

Fixes bloat in contrib ESM bundles, which may reduce bundle size for developers using them.
0.16.36release notes

\htmlData attribute values now support equals signs and surrounding whitespace.
0.16.27release notes

Corrects the size of the [ big delimiter.
0.16.47release notes
Some styling commands now preserve the math font.
0.16.46release notes
Wraps vcenter mpadded in mrow to produce valid MathML.
0.16.45release notes
Removes extra \jot space at the bottom of align, gather, and similar environments.
0.16.44release notes
Long CSS decimals are truncated consistently using makeEm().
0.16.43release notes
Fixes \sout in text mode.
0.16.41release notes
The .katex CSS class now specifies position: relative.
0.16.40release notes
Fixes the middle dot in text mode.
0.16.39release notes
Fixed accent skew when mixed with font specifiers.
0.16.38release notes
Fixed handling of negative-width \hphantom.
0.16.37release notes
Fixed symmetric \smash behavior.
0.16.37release notes
Fixes a version number regression.
0.16.35release notes
Fixes handling of emoji with variation selectors.
0.16.34release notes
SCSS variables are now forwarded to the fonts module.
0.16.33release notes
Fixes italic separation in \mathnormal.
0.16.32release notes
Fixes sizing for fraction commands.
0.16.31release notes
Prevents line breaks after \not.
0.16.30release notes
Fixed \html@mathml macros, including \imath, when used in arguments.
0.16.29release notes
Adds the missing type-definition path so TypeScript consumers can resolve KaTeX types.
0.16.28release notes
Fixes an issue with \mathop followed by an integral symbol.
0.16.26release notes