Apple has released Safari Technology Preview 128

Macos Big Sur Preview Safari Hero
Macos Big Sur Preview Safari Hero (Image credit: Rene Ritchie)

What you need to know

  • Apple has released Safari Technology Preview 128.
  • The new version brings a couple of new features as well as bug fixes and performance improvements.

Apple just has a ton of software releases going on today. In addition to iPadOS 14.7, macOS Big Sur 11.5, and security updates for macOS Mojave and macOS Catalina, the company has also released Safari Technology Preview 128. The latest version includes some performance improvements and bug fixes as well as a couple of new features.

Safari Technology Preview is an experimental version of Safari for users on macOS Big Sur and the upcoming macOS Monterey. The preview allows developers and the curious to test out the latest and greatest features of Apple's browser and provide feedback to the company.

If you want, you can download Safari Technology Preview and test it out for yourself. You can check out the release notes of Safari Technology Preview 128 below:

Web Inspector

Elements Tab

  • Unused inherited CSS variables are now hidden by default in the Styles panel (r278607)
  • CSS variable names are no longer converted to all lowercase in the Computed panel (r278848)


  • Added support for 12 CSS list-style-type values along with other list style fixes (r279165)
  • Fixed CSSOM "set a CSS declaration" for logical properties (r279044)
  • Fixed new snap containers always snapping to the first scroll position (r278862)
  • Fixed Scroll snap offsets interpreted as scroll positions in a scrollable area (r278868)
  • Fixed flex items staying invisible after initial layout (r278659)
  • Fixed text-decoration: underline not applied to web component (r278602)
  • Stopped computing the min or max sizes of flex items twice (r278865)


  • Ignored Intl.NumberFormat feature options when linked-ICU is old (r278697)
  • Optimized JSON.parse with small data by changing Identifier pool mechanism (r278971)
  • Optimized valueOf call via ToPrimitive (r279053)
  • Fixed that Window should behave like a legacy platform object without indexed setter (r278585)

Live Text

  • Added a mechanism to regenerate text in an image element when it changes dimensions (r278747)
  • Changed mouse events to trigger text recognition only if the cursor is moving (r279059)
  • Text selection inside image elements should not be cleared upon resize (r278775)


  • Reworked handling buffer full in SourceBuffer (r278603)

Performance API

  • Implemented performance.timeOrigin (r278665)


  • Adjusted fetch port blocking for ports 990, 989 (r279099)
  • Fixed Document's execCommand() and queryCommand() to throw an exception on non-HTML or non-XHTML documents ** (r278974)
  • Fixed EventSource.constructor to not throw an exception when the URL parameter is an empty string (r278763)
  • Implemented width and height attributes on source elements of [[ picture ]] (r279108)
  • Improved specification compatibility for the outerHTML setter (r278821)
Joe Wituschek

Joe Wituschek is a Contributor at iMore. With over ten years in the technology industry, one of them being at Apple, Joe now covers the company for the website. In addition to covering breaking news, Joe also writes editorials and reviews for a range of products. He fell in love with Apple products when he got an iPod nano for Christmas almost twenty years ago. Despite being considered a "heavy" user, he has always preferred the consumer-focused products like the MacBook Air, iPad mini, and iPhone 13 mini. He will fight to the death to keep a mini iPhone in the lineup. In his free time, Joe enjoys video games, movies, photography, running, and basically everything outdoors.