Release Notes for Safari Technology Preview 35

Safari Technology Preview Release 35 is now available for download for macOS Sierra and betas of macOS High Sierra. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab. This release covers WebKit revisions 218629-219131.


  • Fixed a 50% regression on MotionMark Suites when extended color support was added (r218717)
  • Fixed the bug that Speedometer’s score worsens by 40% when accessibility features are enabled (r218910)


  • Changed image decoding so that when an image appears more than once on a page, decoding to paint one instance repaints them all (r219045)
  • Fixed a frame rate issue that caused getUserMedia to fail on some machines (r218852)
  • Fixed allowing media element to update its state when Mission Control closes the fullscreen window (r218813)
  • Made a change to hide volume controls when AirPlay is active (r218891)
  • Prevented capturing at unconventional resolutions when using the software encoder (r218699)
  • Prevented clearing capture mute from clearing audio mute (r218632)

Web Inspector

  • Added a small delay before showing the progress spinner when loading resources (r219017)
  • Added a toggle button to the left side of the split console navigation bar (r218839)
  • Fixed initial search sometimes being performed twice, producing duplicate results (r219021)
  • Fixed slowness when pausing with a deep call stack by avoiding eagerly generating object previews (r218718)
  • Flipped all go-to-arrow instances in right-to-left mode (r218777)
  • Fixed script timeline bubbles that sometimes appear to miss large events (r218781)
  • Fixed a hang when using “break on all exceptions” throws a stack overflow (r218652)
  • Improved type token background color in the debugger (r219041)


  • Cleaned up Object.entries implementation (r218790)
  • Implemented Object Rest Destructuring (r218861)
  • Made Object.values faster by writing it in C++ (r218697)
  • Removed Reflect.enumerate (r218784)


  • Fixed calling setValue() on contenteditable for ARIA text controls (r218986)
  • Fixed role="none" or role="presentation" on an <iframe> (r219075)


  • Disabled some WebAssembly APIs under CSP (r218951)


  • Fixed a backward compatibility issue with CryptoKey objects stored in the IndexedDB (r218666)

Web APIs

  • Fixed a TypeError in the Fetch API when called with body === {} (r218677)
  • Fixed an issue causing Safari to leave a popup window opened during the beforeunload event (r219039)
  • Included audio/vnd.wave as a valid mime-type for wav files (r218634)


  • Added support for structured serialization of CSS Geometry types (r218644)
  • Fixed @font-face rules with invalid primary fonts never downloading their secondary fonts (r218733)
  • Fixed applying font features only for the particular type of font they are being applied to (r218919)
  • Fixed CSS text properties affecting <video> shadow root (r218655)