Safari Technology Preview 241: Key Updates and Improvements

Safari Technology Preview 241 brings a host of enhancements to web developers and users, focusing on accessibility, CSS capabilities, and animation behavior. This release, available for macOS Tahoe and macOS Sequoia, includes WebKit changes from revision 309287 to 310186. Below, we address common questions about the update.

What is Safari Technology Preview 241 and how do I get it?

Safari Technology Preview 241 is the latest experimental version of Apple's web browser, designed for developers to test upcoming WebKit features before they appear in the stable Safari release. It's available for download on macOS Tahoe and macOS Sequoia. If you already have a previous version installed, you can update directly through System Settings → General → Software Update. This release incorporates WebKit changes between revisions 309287 and 310186, bringing a variety of fixes and new capabilities.

Safari Technology Preview 241: Key Updates and Improvements — Source: webkit.org

What accessibility issues were resolved in this update?

Several important accessibility fixes are included. 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 respected when computing accessible names from element content, enhancing the semantic structure for accessibility tools.

What new CSS features were added?

This release adds two notable CSS features. The stretch keyword is now supported in box sizing properties, giving developers more control over element dimensions. Additionally, CSS scroll anchoring has received stable support, which prevents unexpected page jumps when content above the viewport loads. Scroll anchoring is particularly useful for single-page applications and dynamically loaded content, as it maintains the user's scroll position more reliably.

What animation fix was included?

A key animation issue was resolved: animation-fill-mode now correctly applies viewport-based units after the viewport is resized. Previously, resizing the viewport could cause animations to apply incorrect unit values, leading to visual glitches. This fix ensures that properties using vh, vw, and similar units are properly recalculated and applied during animation fill states, resulting in smoother and more predictable animations across different screen sizes.

What are some other notable CSS fixes?

Multiple CSS bugs were addressed. For instance, the U+2028 LINE SEPARATOR character now renders as a forced line break per the CSS specification. The outline-offset property is no longer inflated for outline: auto on macOS. Font-family serialization now preserves quotes around family names that match CSS-wide keywords or generic families. Additionally, fonts are no longer downloaded if no characters in the document fall within their unicode-range. Other fixes include proper shrinking of flex items with percentage-height images, correct View Transition snapshot color handling, and improved performance for contain: layout.

How can I report issues or learn more?

If you encounter any bugs or have feedback about Safari Technology Preview, you can report them through the WebKit Bugzilla system. Each fix in this release is linked to a specific bug number (e.g., 46151521 for the speechSynthesis fix). For detailed information, visit the WebKit project page or check the release notes on Apple's developer website. Keep your browser updated to benefit from the latest improvements and to ensure compatibility with evolving web standards.