Release Notes for Safari Technology Preview 250

Aug 13, 2026

by Jon Davis

Safari Technology Preview Release 250 is now available for download for macOS Golden Gate and macOS Tahoe. 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: 317507@main…317934@main.

Accessibility

Resolved Issues

  • Fixed VoiceOver reading a stray newline and skipping lines when navigating a <textarea> whose value ends in a line break. (317784@main) (182912872)

CSS

New Features

  • Added support for the spaces value of the ruby-overhang property, which limits annotation overhang to adjacent spaces and punctuation, with none now an alias for spaces. (317569@main) (181808420)
  • Added support for the content property on the ::marker pseudo-element. (317570@main) (182750380)
  • Added support for the text-decoration-inset property. (317571@main) (182750933)
  • Added support for the white-space-trim property. (317573@main) (182751076)
  • Added support for the wrap-inside property. (317574@main) (182751559)

Resolved Issues

  • Fixed a list-style-position: inside marker glyph being painted one device pixel away from the equivalent inline text. (317789@main) (182447949)
  • Fixed text-decoration specified on ::selection never being painted. (317673@main) (182757292)
  • Fixed a text decoration on ::selection not being painted when the selected text had no decoration of its own. (317695@main) (182864748)
  • Fixed a max-content sized block collapsing to zero width when its child used an orthogonal writing mode. (317781@main) (183026896)

Deprecations

  • Removed support for the non-standard text color value; use canvastext instead. (317687@main) (100364547)

Editing

New Features

  • Added support for copying and pasting image/svg+xml data with the Clipboard API, sanitizing the markup on both read and write. (317528@main) (137553836)

JavaScript

New Features

  • Added support for the Explicit Resource Management proposal, including using and await using declarations, Symbol.dispose, DisposableStack, and AsyncDisposableStack. (317894@main) (103209363)
  • Added support for Iterator.zip() and Iterator.zipKeyed() from the Joint Iteration proposal. (317886@main) (180967133)
  • Added JavaScript and WebAssembly feature flags alongside other web feature settings. (317306@main (https://commits.webkit.org/317306@main)) (182210113)

Media

Resolved Issues

  • Fixed a spurious pause and ended event firing on a live HLS stream when playback reached the live edge. (317626@main) (100556746)
  • Fixed a media fragment with an out-of-range hours value being accepted as a valid seek instead of being rejected. (317869@main) (181820705)
  • Fixed a WebVTT cue incorrectly inheriting a preceding line as its identifier across a REGION or STYLE block. (317811@main) (181977285)

Networking

New Features

  • Added initial support for uploading a ReadableStream body with fetch(). (317724@main) (182510365)
  • Added support for the duplex option on Request, which is required when uploading a ReadableStream body. (317768@main) (182802330)

Scrolling

Resolved Issues

  • Fixed scrollIntoView() on an inline element sharing a line with a much taller element scrolling to the top of the line box instead of to the element. (317933@main) (178491868)
  • Fixed paged scrolling with Page Down or the spacebar skipping over intermediate scroll snap points. (317562@main) (182562852)
  • Fixed a crash that could occur while sending a scroll update during window tear-down. (317785@main) (182972245)
  • Fixed re-snapping after layout always preferring a focused element, instead of only when focus has changed. (317892@main) (183146768)

Storage

Resolved Issues

  • Fixed an IndexedDB put() that fails a unique index constraint deleting the record it would have overwritten, leaving the object store with neither the old nor the new record. (317632@main) (181513905)

Web API

Resolved Issues

  • Fixed Digital Credentials get() being rejected in an iframe inside a focused window. (317656@main) (109191868)

Web Inspector

New Features

  • Added support for showing WebAssembly modules in the Sources tab. (317891@main) (182605814)

Resolved Issues

  • Fixed disabling the resource cache overwriting a Cache-Control header already set by the page. (317814@main) (183072123)

WebAssembly

New Features

  • Added support for relaxed SIMD instructions. (317549@main) (180967232)
  • Added support for multiple memories in a single WebAssembly module. (317636@main) (182219080)

WebDriver

New Features

  • Added support for the “consume user activation” extension command, which consumes the current browsing context’s transient user activation and reports whether it was present. (317715@main) (102634281)