Safari 27.2 Updates CSS Standards and Bug Fixes
The latest browser update renames key layout properties and removes cookie lifetime caps to improve cross-domain compatibility.
Updated on Oct. 27, 2026 in Software
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Apple has released Safari 27.2, an update that introduces 20 bug fixes and modifies several web standards. The release notably renames the Grid Lanes flow-tolerance CSS property to fit-tolerance, while maintaining the old name as a deprecated alias.
Why it matters
The change to the fit-tolerance naming convention aligns Safari with new CSS Working Group standards for better semantic clarity. Meanwhile, updates to audio decoding and cookie policies improve compatibility for developers managing cross-domain media and data persistence.
Safari 27.2 sets the default value for the renamed fit-tolerance property at 1em. This release also resolves specific issues where the WebCodecs VideoEncoder stalled on H.264 profiles.
The players
Apple
A global technology company that develops the Safari web browser and maintains the WebKit rendering engine.
WebKit
The open-source browser engine used by Safari, responsible for implementing web standards and processing layout properties.
The details
The fit-tolerance property, originally shipped as flow-tolerance in March 2026, defines how grid elements handle overflow. Developers can use the browser's Web Inspector to identify instances needing the property name update. Additionally, the engine now supports AudioContext.decodeAudioData() for AAC/M4A files to resolve previous encoding errors.
Timeline
March 2026: Grid Lanes property originally shipped in Safari.
October 26, 2026: Apple released Safari 27.2.
The Tech Race
The update aligns Safari with the evolving CSS Working Group property naming standards. This transition ensures that layout properties remain consistent as other browsers adopt the updated fit-tolerance specification.
Developers should update their CSS stylesheets to replace the deprecated flow-tolerance property with the new fit-tolerance naming standard. The removal of the seven-day cookie cap for CNAME-linked domains will also affect how sites manage cross-domain data persistence.
The takeaway
Developers should migrate to the new fit-tolerance property to ensure future compatibility as support for the deprecated alias eventually sunsets. Monitor upcoming WebKit release notes to track if the CSS Working Group mandates further changes to grid-based layout properties.
Further reading
For more information on the latest browser developments, see Software.
Source note: This article includes information reported by WebProNews.
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