# Safari Technology Preview 208 Release Notes Learn about the latest web technology updates in Safari Technology Preview: CSS, JavaScript, Rendering, Scrolling, Web API, Web Authentication, Web Extensions, Web Inspector, and WebRTC. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 208 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: [285487@main…286403@main](https://github.com/WebKit/WebKit/compare/d9d710f8884420dee907e8117e1dcdedeb8b06fc...0ba313f0755d90540c9c97a08e481c192f78c295). ### CSS #### New Features - Added `attr()` fallback support. ([285849@main](https://commits.webkit.org/285849@main)) (136763160) #### Resolved Issues - Fixed combining CSS `clip-path` with any property that creates a new stacking context makes `` element disappear. ([286172@main](https://commits.webkit.org/286172@main)) (86091397) - Fixed resize to not be applied to generated content. ([285644@main](https://commits.webkit.org/285644@main)) (121348638) - Fixed `:not(:has(...))` invalidation. ([285987@main](https://commits.webkit.org/285987@main)) (122689282) - Fixed `@scope` `start` and `end` to be a forgiving selector list. ([286393@main](https://commits.webkit.org/286393@main)) (139471866) ### JavaScript #### New Features - Added support for `Iterator.concat`. ([285587@main](https://commits.webkit.org/285587@main)) (138013723) - Implemented relaxed laneselect SIMD instructions. ([286162@main](https://commits.webkit.org/286162@main)) (138484223) - Enabled support for Iterator Helpers. ([285734@main](https://commits.webkit.org/285734@main)) (138520150) - Added support for `Map.prototype.getOrInsert` and `WeakMap..prototype.getOrInsert`. ([286377@main](https://commits.webkit.org/286377@main)) (138955824) ### Rendering #### Resolved Issues - Fixed `` element with `height: min-content` getting streteched vertically. ([286284@main](https://commits.webkit.org/286284@main)) (137063317) - Fixed support for CSS width and height properties on MathML elements. ([285892@main](https://commits.webkit.org/285892@main)) (138174295) - Fixed Inline content incorrectly positioning around right-to-left and/or vertical `shape-outside` floats. ([286007@main](https://commits.webkit.org/286007@main)) (139076129) - Fixed incorrectly overlapping when a float has `shape-outside: inset`. ([286054@main](https://commits.webkit.org/286054@main)) (139133291) - Fixed right-to-left content failing with a `shape-outside` float. ([286079@main](https://commits.webkit.org/286079@main)) (139198865) - Fixed incorrectly overlapping a float that has `shape-outside: ellipse` in vertical mode. ([286088@main](https://commits.webkit.org/286088@main)) (139208636) - Fixed incorrectly overlapping a float that has `shape-outside: polygon` in right-to-left. ([286099@main](https://commits.webkit.org/286099@main)) (139215719) ### Scrolling #### Resolved Issues - Fixed scrollbar appearance when the used color scheme changes. ([286229@main](https://commits.webkit.org/286229@main)) (138108344) ### Web API #### Resolved Issues - Fixed Gamepad rumble issue where sending two sequential `playEffect()` requests prevents `reset()` from working as expected. ([286286@main](https://commits.webkit.org/286286@main)) (126589062) (FB13733668) ### Web Authentication #### Resolved Issues - Fixed `.catch()` for conditional mediation not getting passed the abort reason that was thrown. ([286208@main](https://commits.webkit.org/286208@main)) (112178073) ### Web Extensions #### New Features - Added declarativeNetRequest support for `initiatorDomains` and `excludedInitiatorDomains`. ([286340@main](https://commits.webkit.org/286340@main)) (97014647) (FB10684115) - Added support for `unless-frame-url` to content blockers. ([286310@main](https://commits.webkit.org/286310@main)) (139456686) #### Resolved Issues - Fixed an issue causing content blockers to not hide content in “about:blank” frames. ([286221@main](https://commits.webkit.org/286221@main)) (134273470) - Fixed `storage.onChanged` returning undefined as the `areaName`. ([285510@main](https://commits.webkit.org/285510@main)) (138086765) - Fixed es-419 support in Web Extensions. ([285875@main](https://commits.webkit.org/285875@main)) (138857112) ### Web Inspector #### Resolved Issues - Fixed the Elements tab DOM tree view reducing deeply-nested nodes to one character wide. ([286163@main](https://commits.webkit.org/286163@main)) (86833831) - Fixed error cases to match new source map specification. ([285541@main](https://commits.webkit.org/285541@main)) (137934436) ### WebRTC #### Resolved Issues - Fixed voice search to not re-prompt for camera or microphone permission after a page-initiated same origin navigation.([285950@main](https://commits.webkit.org/285950@main)) (138122655) --- 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)