Safari 26.3 Released With Vision Pro Fullscreen Upgrade and Zstandard Support

Apple has released Safari 26.3 alongside its latest system updates. This version focuses on performance, usability, and developer tools. Vision Pro users get a visible improvement, while all supported platforms benefit from faster web content handling and important bug fixes. For Vision Pro users running visionOS 26.3, Safari now dims the surroundings automatically when a video enters full screen. The change keeps your focus on the content and improves immersion. It also refines how full-screen controls behave in inline video playback. Apple confirmed the update details in its release notes. Better Fullscreen and Faster Web Performance Safari 26.3 adds support for Zstandard, also known as Zstd. It compresses text-based web assets before delivery and decompresses them quickly on your device. “Zstandard decompresses quickly, reducing the workload on users’ devices. It also compresses fast enough to do on-the-fly, whereas Brotli is typically pre-compressed during your build process.” To use Zstd, you must run Safari 26.3 on iOS 26.3, iPadOS 26.3, visionOS 26.3, or macOS Tahoe 26.3. Developers also get an upgrade to the Navigation API. It now exposes an AbortSignal on NavigateEvent. This allows developers to cancel ongoing tasks reliably when navigation stops. Bug Fixes Across WebKit Safari 26.3 includes several WebKit improvements: Fixed CSS layout loops and position calculation errors Resolved animation jumps with anchor-positioned elements Corrected cursor display issues such as move and resize Improved timestamp handling for touch events Fixed fullscreen button glow in visionOS inline video Restored Video Viewer mode for iframe videos on macOS Resolved live video playback issues when source buffers reset Fixed HDR JPEG rendering problems in certain layouts Corrected a Safe Browsing issue that could wrongly mark entire sites as unsafe Safari 26.3 delivers targeted improvements. It strengthens performance, sharpens fullscreen behavior on Vision Pro, and fixes long-standing WebKit issues across platforms.