# Safari 26.4 adds Grid Lanes, WebTransport, and Keyboard Lock

> Safari 26.4 delivers 44 web features and 191 fixes, including masonry-style Grid Lanes, HTTP/3 WebTransport, and fullscreen keyboard control.

Canonical URL: https://www.devobs.io/news/news-safari-26-4-web-platform-release/
By: Finn Larson
Published: 2026-09-06T11:58:54.648Z
Updated: 2026-09-06T11:58:54.648Z
Event date: 2026-03-24
Section: Web

WebKit released Safari 26.4 on March 24 with 44 web-platform features, 191 fixes, and one deprecation. The [release overview](https://webkit.org/blog/17862/webkit-features-for-safari-26-4/) centers on CSS Grid Lanes, WebTransport, Fullscreen Keyboard Lock, and a long set of layout and standards-alignment fixes.

## Three additions address different application classes

Grid Lanes provides masonry-style placement within CSS Grid, aimed at galleries and feeds whose items have unequal heights. WebTransport adds low-latency bidirectional communication over HTTP/3 and QUIC, with reliable streams and unreliable datagrams available in one connection. Keyboard Lock lets a fullscreen application request keys that the browser normally reserves, useful for games, remote desktops, and creative tools.

The release also makes scroll-driven animations run on the compositor thread, completes WebKit’s blocks-in-inline layout rewrite, and begins broader work on a new Grid layout engine. These are engine changes with potential benefits for existing pages even when developers adopt no new syntax.

## Verify fallback and recovery behavior

Each headline API has a failure mode worth testing. Grid Lanes needs a readable ordinary-grid fallback, especially when source order differs from the visual result. A WebTransport client needs connection timeout, retry, and a fallback transport for unsupported networks or browsers. Keyboard Lock must preserve a clear exit path and should never be the only way to reach essential controls.

This release also removes the deprecated `FontFaceSet` constructor. A dependency audit can catch rare direct use before users do. Teams supporting Safari should run representative MathML, SVG, zoom, anchor-positioning, and WebRTC cases because many fixes sit outside the three headline features. Start with the existing compatibility backlog: issues previously isolated to WebKit are the fastest way to learn whether 26.4 changes application behavior.

## Source references

- <https://webkit.org/blog/17862/webkit-features-for-safari-26-4/>