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Safari Technology Preview 221 Release Notes

Learn about the latest web technology updates in Safari Technology Preview: Accessibility, Forms, JavaScript, Media, PDF, Rendering, Web API, Web Inspector, and WebRTC.

Overview

Safari Technology Preview Release 221 is now available for download for macOS Tahoe and macOS Sequoia. If you already have Safari Technology Preview installed, you can update it in System Settings under General → Software Update.

This release includes WebKit changes between: 295071@main…295660@main

Accessibility

Resolved Issues

  • Fixed aria-expanded attribute support on navigation links. (295356@main) (141163086)

Forms

Resolved Issues

  • Fixed updating scrollbar appearance correctly for the page and <textarea> elements. (295590@main) (151496190)

  • Fixed programmatically assigned File objects to display the correct filename in <input> elements, even without a file path. (295458@main) (152048377)

JavaScript

Resolved Issues

  • Fixed nested negated classes resulting in incorrect matches. (295277@main) (151000852)

Media

Resolved Issues

  • Fixed MP4 seeking with b-frames to prevent out-of-order frame display by suppressing frames with earlier presentation timestamps following the seek point. (295304@main) (140415210)

PDF

Resolved Issues

  • Fixed “Open with Preview” button to open a PDF in the Preview app. (295475@main) (148680145)

Rendering

Resolved Issues

  • Fixed an issue causing a <canvas> element to disappear for one frame if a view transition occurs. (295467@main) (149709642)

Web API

Resolved Issues

  • Fixed escaping < and > when serializing HTML attribute values. (295149@main) (150520333)

Web Inspector

New Features

  • Added support for recording Workers in the Timelines tab. (295485@main) (151721737)

Resolved Issues

  • Fixed pretty-printing CSS to avoid adding a space after the universal selector (*) when followed by a pseudo-class or pseudo-element, preventing unintended changes to CSS selector behavior. (295447@main) (71544976) (FB8906066)

WebRTC

New Features

  • Added support for exposing a default system speaker device. (295206@main) (151761469)

See Also

2025