# Safari Technology Preview 210 Release Notes Learn about the latest web technology updates in Safari Technology Preview: CSS, DOM, JavaScript, Rendering, Web Animations, Web API, Web Extensions, and Web Inspector. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 210 is now [available for download](https://developer.apple.com/safari/resources/) for macOS Sequoia and macOS Sonoma. 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: [286708@main…287517@main](https://github.com/WebKit/WebKit/compare/958f9ea25b9da16154b6edf22cb0ee1246eb90a7...09929bbb98e75b3d9c0ca232c50e75a321f76b14). ### CSS #### New Features - Added support for the `text-autospace` property. ([286750@main](https://commits.webkit.org/286750@main)) (140008990) #### Resolved Issues - Fixed updating the base background color where the root has `color` set explicitly when switching to light or dark modes. ([286833@main](https://commits.webkit.org/286833@main)) (139917332) - Fixed performance of `querySelectorAll()` with `:has()` descendant selectors. ([286908@main](https://commits.webkit.org/286908@main)) (140093151) - Fixed the `unicode-bidi` default for the `` element. ([287175@main](https://commits.webkit.org/287175@main)) (140662417) ### DOM #### New Features - Added support for the `::details-content` pseudo-element. ([286891@main](https://commits.webkit.org/286891@main)) (129786929) ### JavaScript #### Resolved Issues - Fixed: Updated `Intl.DurationFormat` to not include grouping for 2-digit or numeric styles. ([287393@main](https://commits.webkit.org/287393@main)) (140962232) - Fixed `Intl.PluralRules` `pluralCategories` to follow a specific order. ([287411@main](https://commits.webkit.org/287411@main)) (140965181) ### Rendering #### New Features - Implemented `

` and `

` disclosure triangle as a list item. ([286869@main](https://commits.webkit.org/286869@main)) (95148788) #### Resolved Issues - Fixed outside `list-style-position` quirk to only be applicable in quirks mode. ([287114@main](https://commits.webkit.org/287114@main)) (140602985) ### Web Animations #### New Features - Added preview support for Scroll-driven Animations. ([287062@main](https://commits.webkit.org/287062@main)) (140532929) ### Web API #### Resolved Issues - Fixed `Navigation.navigate()` to trigger the `beforeunload` event synchronously. ([286919@main](https://commits.webkit.org/286919@main)) (139628818) - Fixed `innerText` behavior for `

` and `

`. ([286799@main](https://commits.webkit.org/286799@main)) (140172890) ### Web Extensions #### New Features - Added support for `documentId` in `webNavigation`. ([287408@main](https://commits.webkit.org/287408@main)) (137532909) ### Web Inspector #### New Features - Added support for sending Android user agents using the device override menu when Web Inspector is connected to a remote device. ([287092@main](https://commits.webkit.org/287092@main)) (139305520) #### Resolved Issues - Fixed the overview icon to be inverted dark mode in the Graphics tab. ([287110@main](https://commits.webkit.org/287110@main)) (140602803) - Fixed recorded WebGL objects not getting highlighted correctly in the Graphics tab. ([287127@main](https://commits.webkit.org/287127@main)) (140625113) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)