Release Notes for Safari Technology Preview 233

Dec 8, 2025

by Jon Davis

Safari Technology Preview Release 233 is now available for download for macOS Tahoe and macOS Sequoia. 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: 302450@main…303091@main.

Animations

Resolved Issues

  • Fixed incorrect overlap calculations for transform animations including translate, scale, and rotate properties. (303045@main) (88383253)

HTML

New Features

  • Added support for enhanced HTML select parsing to allow <select> elements to include <optgroup>, <option>, and <hr> at deeper nesting levels. (302480@main) (163927485)

MathML

New Features

  • Added support for the MathML scriptlevel attribute, mapping it to CSS math-depth as a presentational hint. (302841@main) (164469677)

Resolved Issues

  • Fixed mpadded elements in RTL (dir="rtl") to respect lspace. (303070@main) (164740784)

Rendering

Resolved Issues

  • Fixed an issue where fixed positioned elements were not rendered correctly in right-to-left pages using the vertical-rl writing mode. (302542@main) (161712734)

Web API

New Features

  • Added support for reading Blob.stream() with a BYOB (getReader({mode:'byob'})) reader. ( 302787@main ) (164307723)

Resolved Issues

  • Fixed Trusted Types to correctly send CSP violation reports when a default policy returns an invalid javascript: URL or throws an exception. (302543@main) (160960418)
  • Fixed NavigateEvent to correctly fire an AbortSignal when a navigation is aborted. (302591@main) (163957784)
  • Fixed NavigateEvent.sourceElement to correctly reference elements from different browsing contexts. (302504@main) (163962362)

Web Inspector

New Features

  • Added support for capturing console.screenshot images within a Worker, including handling of ImageData, ImageBitmap, OffscreenCanvas, various CanvasRenderingContext types, and valid base64 data: URLs. (302778@main) (98223234)