Release Notes for Safari Technology Preview 218

Apr 30, 2025

by Jon Davis

Safari Technology Preview Release 218 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: 293327@main…293898@main

CSS

New Features

  • Added support for crossorigin() and referrerpolicy() modifiers on CSS image loads. (293647@main) (149166339)

Resolved Issues

  • Fixed @font-face font-family descriptor to not allow a list of values. (293892@main) (142009630)
  • Fixed placeholder visibility to update on input type change. (293346@main) (148681639)
  • Fixed an issue where float boxes, selections, and carets were incorrectly painted inside skipped subtrees.(293358@main) (148741142)
  • Fixed incorrect getBoundingClientRect() inside skipped subtree on an out-of-flow positioned box. (293428@main) (148770252)
  • Fixed: Updated the CSS random() function implementation to match the latest spec changes. (293439@main) (148868731)
  • Fixed: Replace match-element with element-shared in the random() function to match the standard changes. (293474@main) (148920346)
  • Fixed making <pre> and other elements use logical margins in the User-Agent stylesheet. (293670@main) (149212392)

JavaScript

New Features

  • Added more support for Temporal. (293864@main) (75685318)

Resolved Issues

  • Fixed iterator helpers incorrectly closing iterators on early errors. (293842@main) (148774612)

  • Fixed Iterator.prototype.reduce failing with an undefined initial parameter. (293797@main) (149470140)

Lockdown Mode

New Features

  • Added support for more web fonts in Lockdown Mode by replacing a fragile hard-coded allowlist with a safe parser that handles a broader range of fonts without compromising security. (293728@main) (149314760)

Rendering

Resolved Issues

  • Fixed an issue to allow images in scroll containers to load when they are near the viewport rather than when they are intersecting the viewport. (293552@main) (118706766)
  • Fixed incorrect ruby annotation positioning in sideways-lr. (293572@main) (148713073)
  • Fixed: Prevented hit testing content inside a skipped subtree. (293361@main) (148741508)

SVG

New Features

  • Added support for pointer-events="bounding-box" for SVG group containers. (293473@main) (148181592)

Web API

Resolved Issues

  • Fixed an issue where pending utterances do not receive an error event when speech synthesis is cancelled.(293536@main) (148731039)

Web Extensions

New Features

  • Added support for the request-method content blocker trigger field. (293746@main) (148474901)

Resolved Issues

  • Fixed converting declarativeNetRequest rules so that higher numbers are treated as higher priority. (293546@main) (145570245) (FB16607998)
  • Fixed an issue causingwasm-unsafe-eval to not get parsed as a valid CSP keyword. (293854@main) (147551225)
  • Fixed and issue that prevented loading a web accessible resource from a subframe at about:blank. (293839@main) (149494286)

Web Inspector

New Features

  • Added support in the Debugger tab for stepping over an await statement as though it is synchronous code. (293628@main) (149133320)

WebRTC

New Features

  • Added support for RTCRtpScriptTransformer.generateKeyFrame to take a rid parameter. (293633@main) (148592676)