Release Notes for Safari Technology Preview 220

May 28, 2025

by Jon Davis

Safari Technology Preview Release 220 is now available for download for macOS Sequoia and macOS Sonoma. 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: 294488@main…295070@main

CSS

New Features

  • Added support for field-sizing to override the default sizing behavior of form elements and adjust size to fit their contents. (295370@main) (151949208)

Resolved Issues

  • Fixed grid sizing with inline-size containment and auto-fit columns is incorrectly sized. (295023@main) (108897961)
  • Fixed a bug where an anchor-positioned element does not properly render when it’s initially hidden from view, then shown. (294924@main) (148608785)

DOM

Resolved Issues

  • Fixed the serialization of CDATASection nodes in HTML. (294547@main) (150739105)

JavaScript

New Features

  • Added support for @@dispose and @@asyncDispose from the Explicit Resource Management Proposal behind runtime flag. (294592@main) (150816114)
  • Added support for SuppressedError from the Explicit Resource Management Proposal behind runtime flag. (294774@main) (151132111)
  • Added support for DisposableStack constructor from the Explicit Resource Management Proposal behind runtime flag. (294880@main) (151280591)

Media

Resolved Issues

  • Fixed MediaSession to handle SVG icons with subresources. (294499@main) (150665852)
  • Fixed MediaCapabilitiesDecodingInfo.configuration to be correctly populated even when .supported is false. (294957@main) (150680756)

Rendering

Resolved Issues

  • Fixed invisible <audio> controls when transformed due to incorrect coordinate space calculations for clipped child elements. (294694@main) (150526971)
  • Fixed centering text for <input type=button> elements with display: flex. (294785@main) (151148821)
  • Fixed showing a resize cursor even when text overlaps the resize control. (294907@main) (151309503)

Web Animations

Resolved Issues

  • Fixed CSS scroll-driven animations on pages using requestAnimationFrame to animate correctly after navigating away and back to the page. (294889@main) (141528296)

Web API

Resolved Issues

  • Fixed making the SpeechRecognition interface available only within a secure context. (294887@main) (151240414)

Web Inspector

Resolved Issues

  • Fixed parsing sourcemaps asynchronously so that large sourcemaps do not block rendering. (294875@main) (151269154)

WebRTC

Resolved Issues

  • Fixed the configurationchange event to fire when a microphone’s audio unit changes its echo cancellation mode, ensuring web pages are notified of such changes to update track settings accordingly. (294839@main) (150770940)