Release Notes for Safari Technology Preview 62

Safari Technology Preview Release 62 is now available for download for macOS High Sierra and the beta of macOS Mojave. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab on macOS High Sierra and in the Software Update pane of System Preferences on macOS Mojave. This release covers WebKit revisions 233728-234197.

Known Issues

  • This release of Safari Technology Preview for macOS Mojave betas does not render text properly in the Smart Search Field when in Dark Mode.
  • This release of Safari Technology Preview for macOS Mojave betas does not have a usable WebDriver implementation; safaridriver hangs when processing the New Session command.

Intelligent Tracking Prevention

  • Added an experimental ITP Debug Mode to be used only when actively debugging, not to remain enabled (r234080, r234108)


  • Changed to canonical language tags in the Internationalization API (r234127)
  • Fixed the Generator and AsyncGeneratorMethod prototype (r233855)
  • Fixed the JSON.stringify replacer to use isArray instead of JSArray checks (r233918)
  • Fixed the iterator of Array.keys() to return the object in the correct order (r233740)
  • Fixed JavaScript URL to provide the correct result when frame is navigated (r233793)
  • Changed JSON.stringify to emit properties included in the prototype chain for entries in the second array argument (r233924)


  • Changed to require the document to be visible for fullscreen video (r233865)
  • Disabled all network caching for HLS streams. (r233738)
  • Fixed the transition for the first Picture-in-Picture from Fullscreen (r234051)
  • Changed HLS resources with remote sub-resources to taint media elements (r234055)
  • Improved WebGL selection of GPU driving the current display (r234074)


  • Fixed newly added float elements to trigger full layout on the block (r233767)

Dark Mode

  • Improved the visibility of spelling and grammar markers in Dark Mode (r233814)


  • Limited editing selections to within Shadow DOM boundaries (r233778)

Web Inspector


  • Implemented support for margin-box as reference box and box shape (r233886)
  • Added full support for -webkit-clip-path on SVG elements (r233835, r234136)

Web Animations

  • Changed to discrete interpolation between font-styles with a keyword value (r233935)
  • Changed to discrete interpolation between lengths with an auto value (r233892)


  • Added support for calc() in CSS Grid gutter properties (r234131)


  • Fixed the ability to remove the database file of a sub-frame (r233777)


  • Fixed pressing tab to highlight items on a webpage when voiceover enabled (r234112)