# Safari Technology Preview 179 Release Notes Learn about the latest web technology updates in Safari Technology Preview: CSS, HTML, HTTP, Media, SVG, Web API, Web Inspector, and WebGL. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 179 is now [available for download](https://developer.apple.com/safari/resources/) for macOS Sonoma beta and macOS Ventura. 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: [266624@main…267815@main](https://github.com/WebKit/WebKit/compare/d87a70ea254bd9a81675a7fe688be40987b6a621...369af365da813ddc565c523c65aedba89c202acd). ### CSS #### New Features - Added support for `mask-border` properties. ([267460@main](https://commits.webkit.org/267460@main)) - Added support for the `cap` unit. ([267315@main](https://commits.webkit.org/267315@main)) - Added support for the `` parameter in `ray()`. ([267459@main](https://commits.webkit.org/267459@main)) - Added new relaxed parsing behavior for CSS Nesting. ([267549@main](https://commits.webkit.org/267549@main)) - Added support for `xywh()` shape. ([267789@main](https://commits.webkit.org/267789@main)) - Added support for `offset-position: normal` for CSS Motion Path. ([267657@main](https://commits.webkit.org/267657@main)) - Added support for the `rcap`, `rex`, `ric`, and `rch` units. ([267321@main](https://commits.webkit.org/267321@main)) - Added new typed OM factory functions for font and root font relative units. ([267437@main](https://commits.webkit.org/267437@main)) - Added support for the `coord-box` parameter in `ray()`. ([267566@main](https://commits.webkit.org/267566@main)) - Added `offset-position` support for `circle()` and `ellipse()`. ([267810@main](https://commits.webkit.org/267810@main)) #### Resolved Issues - Fixed the `font-family` descriptor for `@font-palette-values` to accept multiple values. ([267411@main](https://commits.webkit.org/267411@main)) - Fixed CSS `@imports` in HTML getting mistakenly hidden from the CSS preload scanner when missing a semi-colon and space. ([267322@main](https://commits.webkit.org/267322@main)) - Fixed `:nth-child()` invalidation when not in subject position. ([267600@main](https://commits.webkit.org/267600@main)) - Fixed `:has(:host)` invalidation. ([267773@main](https://commits.webkit.org/267773@main)) - Fixed `:has(:nth-child())` invalidation and related. ([267771@main](https://commits.webkit.org/267771@main)) - Fixed handling dynamic updates to viewport units when used in `@property` initial value. ([267590@main](https://commits.webkit.org/267590@main)) - Fixed the `` implementation for `offset-path`. ([267556@main](https://commits.webkit.org/267556@main)) - Fixed `` implementation for `offset-path`. ([267524@main](https://commits.webkit.org/267524@main)) - Fixed serialization to always serialize implicit `&` and an implicit nested rule. ([267531@main](https://commits.webkit.org/267531@main)) - Fixed the serialization of percentages in `color-mix()`. ([267596@main](https://commits.webkit.org/267596@main)) - Fixed the check for in-progress layout when setting a containing block rect for `ray()` used with `motion-path`. ([267479@main](https://commits.webkit.org/267479@main)) - Fixed adding fine-grained invalidation support for selectors containing `:slotted()`. ([267326@main](https://commits.webkit.org/267326@main)) - Fixed rounding of `` type to round half towards positive infinity. ([267339@main](https://commits.webkit.org/267339@main)) - Fixed fine-grained invalidation for `:host` pseudo-class in non-subject position. ([267355@main](https://commits.webkit.org/267355@main)) - Fixed the container for the `::part` pseudo-element to be selected from the originating element tree. ([267421@main](https://commits.webkit.org/267421@main)) - Fixed serialization of `infinity` and `-infinity` in colors. ([267544@main](https://commits.webkit.org/267544@main)) - Fixed `lab`, `lch`, `oklab`, `oklch` components to be clamped to appropriate ranges. ([267555@main](https://commits.webkit.org/267555@main)) - Fixed `coord-box` to use `border-radius` for CSS Motion Path. ([267613@main](https://commits.webkit.org/267613@main)) - Fixed `color-mix()` to not serialize to legacy color syntax. ([267626@main](https://commits.webkit.org/267626@main)) - Fixed resolving the size of a replaced element by using its intrinsic size as the width. ([267648@main](https://commits.webkit.org/267648@main)) - Fixed determining non-orthogonal grid item’s columnAxisPosition by considering fallback alignment for first/last baseline. ([267811@main](https://commits.webkit.org/267811@main)) ### HTML #### New Features - Added support for the `name` attribute in the `

` element. ([267756@main](https://commits.webkit.org/267756@main)) #### Resolved Issues - Fixed `` not returning the correct value when a decimal is entered. ([267581@main](https://commits.webkit.org/267581@main)) - Fixed dynamic handling of `` elements. ([267498@main](https://commits.webkit.org/267498@main)) - Fixed URL encoding of `` elements. ([267585@main](https://commits.webkit.org/267585@main)) - Fixed URL encoding of SVG `` elements. ([267593@main](https://commits.webkit.org/267593@main)) - Fixed empty value attributes to not be ignored on image input types. ([267592@main](https://commits.webkit.org/267592@main)) ### HTTP #### Resolved Issues - Fixed COOP header breaking back and forward behavior when client-side redirects are involved. ([267553@main](https://commits.webkit.org/267553@main)) ### Media #### New Features - Added support for WebRTC HEVC RFC 7789 RTP Payload Format. ([267677@main](https://commits.webkit.org/267677@main), [267862@main](https://commits.webkit.org/267862@main)) #### Resolved Issues - Fixed WebCodecs VideoEncoder configure to resolve its promise for unknown codecs. ([267668@main](https://commits.webkit.org/267668@main)) - Fixed handling `NaN` in audio delay curves. ([267589@main](https://commits.webkit.org/267589@main)) - Fixed setting the color space for WebCodecs/WebRTC VP9 for libvpx encoders. ([267638@main](https://commits.webkit.org/267638@main)) ### SVG #### New Features - Added support for SVG ``. ([267349@main](https://commits.webkit.org/267349@main)) ### Web Animations #### Resolved Issues - Fixed `color-scheme` to support discrete animation. ([267750@main](https://commits.webkit.org/267750@main)) ### Web API #### New Features - Added support for `window.clientInformation` in terms of `window.navigator`. ([267625@main](https://commits.webkit.org/267625@main)) #### Resolved Issues - Fixed checking for `NaN` when creating a DelayNode for WebAudio. ([267650@main](https://commits.webkit.org/267650@main)) - Fixed `element.querySelector(":has(:scope *)")` to never match. ([267809@main](https://commits.webkit.org/267809@main)) #### Deprecations - Removed `HTMLMediaElement.webkitHasClosedCaptions` and `HTMLMediaElement.webkitClosedCaptionsVisible`. ([267780@main](https://commits.webkit.org/267780@main)) ### Web Inspector #### New Features - Added support for 2D OffscreenCanvas. ([262388@main](https://commits.webkit.org/262388@main), [267488@main](https://commits.webkit.org/267488@main)) - Added a specialized editor for the CSS `steps()` timing function. ([267484@main](https://commits.webkit.org/267484@main)) #### Resolved Issues - Fixed objects logged to the console with multiple private fields that use the same name. ([267483@main](https://commits.webkit.org/267483@main)) ### WebGL #### New Features - Added support for `EXT_blend_func_extended`. ([267775@main](https://commits.webkit.org/267775@main)) - Enabled support for `WEBGL_clip_cull_distance` by default. ([267795@main](https://commits.webkit.org/267795@main)) --- 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)