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Apple Releases Safari Technology Preview 150 – Brings Bug Fixes and Performance Improvements

Apple Releases Safari Technology Preview 150 – Brings Bug Fixes and Performance Improvements

Apple has released Safari Technology Preview 150, the latest version of their developer preview web browser. The preview version of Apple’s popular browser offers developers and other interested users the ability to try out features that may or may not, debut in future public release versions of Safari.

‌Safari Technology Preview‌ release 150 includes bug fixes and performance improvements for Web Inspector, CSS, Shadow DOM, JavaScript, Web Animations, Web Share, WebAuthn, Web API, Rendering, and Accessibility.

‌The current ‌Safari Technology Preview‌ release is built on the Safari 16 update and it includes features coming in macOS Ventura. It adds support for Live Text in videos and images, new web technologies, web push Passkeys, improved Safari Web Extensions, and more.

The preview is available for both macOS Monterey and macOS Ventura. It is no longer available for macOS Big Sur.

Release 150

Note: Shared Tab Groups and syncing for Tab Groups, Website Settings, and Web Extensions are not enabled in this release.

Web Inspector

  • Elements Tab
    • Changed CSS autocomplete so that the most commonly used property accounts for fuzzy-matching (252194@main)
    • Fixed property usage counts to ignore variables in CSS autocomplete (252195@main)
    • Make popover for resolved CSS variable values consistent with other popovers (252133@main)
    • Automatically hide the CSS documentation popover when navigating away (252175@main)
  • Sources Tab
    • Provided an option for controlling whether local overrides entirely replace or have some passthrough (251884@main)
  • Network Tab
  • Timelines Tab
    • Fixed Screenshots timeline overview records to adjust their position when zooming in or zooming out (252148@main)
  • Layers Tab
    • Fixed reasons for compositing for an element with clip-path and composited descendants (252354@main)
  • Search Tab
    • Improved search performance for short queries on many sites (252279@main)
  • Device Settings and Develop menu
    • Updated user-agent overrides to match options in Safari 16 (251881@main)


Shadow DOM

  • Fixed :focus pseudo-class failing to repaint on a shadow host when the focus moves from outside the page to inside a shadow tree (252261@main)
  • Fixed :focus-within pseudo-class not getting updated when the frame loses or gains focus (252324@main)
  • Fixed :lang pseudo-class to work across shadow boundaries (252099@main)
  • Fixed the :host() function pseudo-class to only accept a single compound-selector (252110@main)
  • Fixed vw units to get updated inside shadow trees as the frame is resized (252149@main)


  • Adjusted ArrayBuffer size tracking only when full garbage collection happens (252368@main)
  • Adopted Intl.NumberFormat v3 spec change for useGrouping option (252013@main)
  • Fixed interpretation of the fractional part of an ISO8601 Duration string (251809@main)

Web Animations

  • Added support for custom properties in Animation.commitStyles() (251858@main)
  • Added support for custom properties in JavaScript-originated animations (251856@main)

Web Share


  • Added getPublicKey and getPublicKeyAlgorithm methods to AuthenticatorAttestationResponse (251844@main)
  • User handles that are too long or too short are now rejected (251938@main)
  • Empty RP ids are now rejected (252142@main)
  • Added support for authenticators over CCID (252425@main)
  • Fixed passing CBOR-encoded extensions along during assertions (252626@main)


  • Designed an intentional way to invalidate platform font caches (251845@main)
  • Fixed PushManager in private browsing (251831@main)
  • Fixed IntersectionObserver stopping tracking when ⌘+ (Command-plus) is used to zoom in (251829@main)
  • Fixed ⇧⇥ (Shift-Tab) when focused in the middle of a contenteditable element (252029@main)
  • Fixed an issue where SameSite=Lax cookies were sometimes not sent on link navigations (252341@main)
  • Fixed SVGs loading an external file via <use> ignoring the ServiceWorker when offline (252132@main)
  • Fixed video.currentSrc to not be reset when a new load errors (251899@main)
  • Fixed an issue where inserting an iframe erroneously performs a micro-task checkpoint. (252015@main)


  • Fixed padding on a flex-based horizontal scroller preventing the last item from being fully viewable (251770@main)
  • Fixed clipping of absolutely positioned descendants of a transformed element with overflow: hidden (252387@main)
  • Implemented aspect-ratio mapping for the canvas element (252001@main)
  • Reduced memory use for for non-animated compositing layers with zero opacity (251965@main)
  • Fixed re-inserting <object> that previously rendered fallback content (251903@main)


  • Fixed WebSpeech to correctly allow the use of selected voices (252346@main)

While the preview is intended for use by developers and advanced users, in order to provide Apple with feedback on the development of the Safari browser, it can be run side-by-side with the release version of Safari. The app doesn’t require a developer account to download and install. For more information, visit the Safari Technology Preview website.