What's New in Safari Technology Preview 241? Key Fixes and Features Explained

Safari Technology Preview 241 is now available for download on macOS Tahoe and macOS Sequoia. If you already have it installed, you can update via System Settings → General → Software Update. This release includes substantial WebKit improvements, from accessibility enhancements to new CSS capabilities and bug fixes. Below, we break down the most important changes in a Q&A format to help you understand what's new and how it impacts web development.

1. What accessibility issues were resolved in Safari Technology Preview 241?

Several critical accessibility bugs have been fixed. First, calling speechSynthesis.cancel() no longer removes utterances queued by subsequent speechSynthesis.speak() calls, ensuring smoother speech output. Second, incorrect bounding boxes for MathML table rows and cells have been corrected, improving screen reader accuracy. Third, comboboxes now properly forward focus to their aria-activedescendant, allowing assistive technologies to interact with list items. Finally, the aria-owns attribute is now correctly considered when computing accessible names from element content. These changes make web content more inclusive for users relying on screen readers and other assistive tools.

2. How does the update fix animation and viewport-related problems?

Two key animation issues were addressed. The animation-fill-mode property now correctly applies viewport-based units (like vw, vh) after the viewport is resized, preventing visual glitches in animations that depend on viewport dimensions. Additionally, View Transition snapshots were being stored in sRGB color space incorrectly, causing rendering issues with non-sRGB colors. This fix ensures that color-accurate transitions work as expected. Developers creating animated effects will find these updates essential for maintaining visual consistency across different screen sizes and color profiles.

3. What new CSS features does Safari Technology Preview 241 add?

Two major CSS features debut in this release. First, support for the stretch keyword in box sizing properties (like width, height, and min/max sizing) has been added, giving developers more flexibility in responsive layout design. Second, CSS scroll anchoring is now stable and enabled by default. Scroll anchoring prevents jarring page jumps when content loads above the user's viewport, improving the browsing experience on dynamic pages. These features align Safari with modern CSS standards and enhance developer control over layout behavior.

4. Which notable CSS rendering bugs were fixed in this release?

Numerous rendering quirks have been squashed. The U+2028 LINE SEPARATOR now correctly renders as a forced line break per the CSS specification. outline-offset with outline: auto on macOS no longer inflates incorrectly. Font family serialization preserves quotes around family names matching CSS-wide keywords or generic families. A fix prevents downloading fonts when no characters in the document fall within the font's unicode-range. The color: initial value now resolves correctly in dark appearance mode, and underlines are no longer split when a ruby base expands due to long ruby text. These adjustments ensure more predictable and standards-compliant rendering.

5. How does this release improve performance and layout handling?

Performance receives a boost with a fix for contain: layout, which previously caused significantly slower forced layouts when all siblings created their own formatting context. Additionally, a flex item containing a percentage-height image now shrinks correctly around the image, solving a common layout inconsistency. A regression where media queries could fail to resolve correctly has also been fixed. These changes reduce unnecessary layout recalculations and improve page responsiveness, especially in complex CSS grid or flexbox layouts.

6. What fixes were made for popovers, anchor positioning, and dark mode?

Several edge-case bugs have been resolved. Nested children of a popover element with position: absolute now render correctly. An element with display: contents now establishes an anchor scope when using anchor-scope, enabling proper anchor positioning. Changing color-scheme now repaints the background of composited iframes as expected. And a fix ensures that color: initial works properly in dark mode. These updates improve compatibility with modern CSS features like popovers, anchor positioning, and dark mode support.