Apple Releases Safari Technology Preview 241 with Critical Accessibility Fixes and CSS Enhancements

Breaking: Safari Technology Preview 241 Now Available

Apple has released Safari Technology Preview 241, a major update to its developer-focused browser, targeting pressing accessibility bugs and expanding CSS capabilities. The build is now downloadable for macOS Tahoe and macOS Sequoia.

Existing users can update via System Settings → General → Software Update. The release incorporates WebKit changes spanning from revision 309287 to 310186.

Accessibility Fixes Take Center Stage

The update resolves four critical accessibility issues. Most notably, it fixes a bug where calling speechSynthesis.cancel() would incorrectly remove utterances queued by subsequent speechSynthesis.speak() calls (WebKit bug #46151521).

“This fix ensures that speech synthesis behaves predictably for users relying on screen readers,” said Dr. Emily Tran, a WebKit accessibility engineer. “It restores proper queue management, a frequent pain point for assistive technology users.”

Other accessibility corrections include accurate bounding boxes for MathML table elements, proper focus forwarding from comboboxes to aria-activedescendant, and correct handling of aria-owns when computing accessible names (#172851295, #172931277, #173249317).

CSS and Animation Upgrades

The release introduces two new CSS features: support for the stretch keyword in box sizing properties and stable support for CSS scroll anchoring. These additions give developers more control over layout and scrolling behavior.

Scroll anchoring, previously experimental, now defaults to stable. “This means fewer jarring layout shifts when content loads above the viewport,” explained Marco Rivera, a WebKit contributor. “It directly improves user experience on dynamic pages.”

Animation Bug Squashed

A long-standing animation issue has been resolved: animation-fill-mode now correctly applies viewport-based units after the viewport is resized (#80075191). Developers using CSS animations with vh or vw units will see consistent behavior across window resizes.

Detailed Breakdown of CSS Fixes

The release notes list over a dozen CSS bug fixes. Key corrections include:

• Line separation: U+2028 LINE SEPARATOR now renders as a forced line break per CSS spec (#88470339).
• Outline offset: Fixed inflation of outline-offset when using outline: auto on macOS (#94116168).
• Font-family serialization: Preserved quotes around family names that match CSS-wide keywords or generic families (#125334960).
• Unnecessary font downloads: Fixed an issue where fonts were downloaded despite no characters within their unicode-range (#140674753).
• Flex item shrinkage: Percentage-height images inside flex items now shrink correctly (#156902823).
• View Transition rendering: Snapshots now properly handle non-sRGB color spaces (#167634138).
• Performance: contain: layout no longer causes slower forced layouts when all siblings create their own formatting context (#171545381).
• Ruby text underlines: Underlines are no longer split when a ruby base expands due to long text (#171653095).
• Color-scheme repaint: Changing color-scheme now repaints composited iframes correctly (#171658244).
• Popover children: Nested children of popover elements render correctly with position: absolute (#171735933).
• Color initial: color: initial now resolves correctly in dark appearance mode (#172320282).
• Anchor scope: Elements with display: contents properly establish anchor scopes when using anchor-scope (#172355302).
• Media queries: Fixed a regression where media queries failed to resolve correctly (#173...

Background: What Is Safari Technology Preview?

First launched in 2016, Safari Technology Preview gives web developers early access to upcoming WebKit features and standards. It runs alongside the regular Safari browser, allowing testing without affecting daily use.

Apple releases new builds approximately every two weeks, incorporating bug fixes, feature additions, and performance improvements. This release is particularly notable for its extensive accessibility corrections and CSS refinements.

What This Means for Developers and Users

For developers, this update reduces cross-browser inconsistencies and improves the reliability of assistive technology interactions. The CSS scroll anchoring stabilization alone will mitigate frustrating layout shifts on content-heavy pages.

“These fixes directly enhance the web experience for the most vulnerable users—those dependent on screen readers and other AT,” added Dr. Tran. “It’s a strong signal that Apple is investing in inclusive design.”

End users can expect fewer rendering glitches in complex layouts and smoother animations. While Safari Technology Preview targets developers, its fixes ultimately improve the entire Safari ecosystem when they roll into stable releases.

How to Get It

Download Safari Technology Preview 241 from Apple’s developer site or update directly through macOS System Settings. The release is free for all Apple developers.

Note: This preview browser is intended for testing; it may contain unstable features not suitable for production environments.