What's New in Safari Technology Preview 242? Key Updates and Fixes

Safari Technology Preview Release 242 is now available for download on macOS Tahoe and macOS Sequoia. This update brings a host of improvements across Accessibility, CSS, Forms, and HTML, along with numerous bug fixes. Below, we answer the most common questions about what this release includes and how to get it.

How can I download or update Safari Technology Preview 242?

If you already have Safari Technology Preview installed, updating is straightforward. Go to System Settings → General → Software Update, and the latest version will appear for installation. For a fresh download, visit the official Apple Developer website. This release is compatible with both macOS Tahoe and macOS Sequoia. The WebKit changes included span from build 310187 to 310599.

What accessibility improvements are included in this release?

Two significant accessibility issues were resolved:

• VoiceOver fix: Images with role="presentation" no longer cause VoiceOver to read their text content, improving screen reader usability. (159304061)
• Customizable select elements: macOS accessibility now properly supports custom <select> elements using appearance: base-select. (173696010)

What new CSS features does Safari Technology Preview 242 introduce?

This release adds support for two CSS features:

• CSS attr() function from CSS Values Level 5 (173700363). This allows authors to retrieve the value of an attribute on an element and use it as a CSS value.
• oblique-only value for font-synthesis-style (173730766), as defined in CSS Fonts Level 4. This gives finer control over font style synthesis.

What CSS issues were resolved in this update?

A number of CSS bugs were fixed, including:

• @media (prefers-color-scheme: dark) now correctly matches inside iframes with color-scheme: dark (142072593).
• position-try-order uses the containing block’s writing mode (169501069).
• Percent-height replaced elements no longer compute stale preferred widths in shrink-to-fit containers (171184282).
• Table cell nowrap minimum width calculation quirk now only applies in quirks mode (171410252).
• Checkbox outlines are now properly aligned (172742551).
• Anchor-positioned elements anchored to children of sticky boxes now stick correctly (172884148).
• Pseudo-elements are sorted by tree order correctly (173032203).
• Ligatures no longer cause non-zero layout width for text with font-size: 0 (173840805).
• :in-range and :out-of-range pseudo-classes update when readonly changes (173978657).
• view-timeline-inset serialization now coalesces identical values (174096313).

What changes were made to forms in this release?

One form-related bug was fixed: <select multiple> now correctly fires the onchange event when the mouse button is released far outside the element. Previously, if the user dragged outside the dropdown and released, the change event might not fire. This fix ensures consistent behavior across platforms. (173882861)

What HTML enhancements and fixes are included?

This release adds support for the closedby attribute on <dialog> elements (173974767), which allows developers to specify how a dialog can be dismissed. Additionally, several HTML parser fixes improve robustness:

• The fast path correctly processes escaped attribute values longer than one character (173673581).
• Nested <li> elements are now properly detected (173983892).
• The adjusted current node is used for MathML and SVG integration point checks (174096305).