Apple has released Safari Technology Preview 243, bringing a host of improvements and bug fixes for developers and early adopters. This update covers everything from accessibility enhancements to CSS and animation tweaks, all aimed at refining the browsing experience. Below, we answer the most common questions about this release, so you can quickly understand what’s changed and how it affects your workflow.
- How do I get or update Safari Technology Preview 243?
- What key accessibility fixes are included?
- What animation issues were resolved in this version?
- Are there any new CSS features or properties added?
- Which important CSS rendering bugs have been fixed?
- Were there any performance improvements for selectors?
- What’s the WebKit change range for this release?
How do I get or update Safari Technology Preview 243?
If you’re on macOS Tahoe or macOS Sequoia, you can download a fresh copy from Apple’s developer site. For those who already have Safari Technology Preview installed, updating is straightforward: open System Settings, go to General → Software Update, and the new version will appear. It’s that simple. This release replaces your previous preview version, so you don’t need to uninstall anything manually.
What key accessibility fixes are included?
Several important accessibility issues have been tackled. For instance, the contextmenu event now fires correctly for elements inside <iframe> when triggered by keyboard or assistive technology (like VoiceOver’s VO+Shift+M). Color picker inputs can also be activated using VoiceOver’s press action again. Additionally, the invalidation of aria-hidden="true" works properly when focus lands inside the hidden subtree. VoiceOver support for basic <select> elements has been improved, including closing the popover upon selection and fixing accessibility path positioning when CSS transforms are applied. These changes make the technology preview more usable for people relying on screen readers and other assistive tools.
What animation issues were resolved in this version?
Two noteworthy animation bugs were fixed. First, !important declarations now correctly override CSS animation values even when CSS transitions are running on the same property. Previously, the !important rule could be ignored during concurrent animations, causing unexpected visual results. Second, a problem with identity matrix decomposition that generated invalid quaternions has been resolved. This was leading to incorrect transform animations—objects might have rotated or scaled erratically. Now, transform sequences behave as intended, ensuring smoother, more predictable motion effects.
Are there any new CSS features or properties added?
Yes, two additions stand out. First, support for contain: style has been extended to apply to CSS quote counters, aligning with the CSS Containment Level 2 specification. This helps developers better control style containment for quotes and counter properties. Second, the insert keyword is now available for the text-autospace property. This keyword tweaks automatic spacing around inserted content (like punctuation), giving designers finer control over typography.
Which important CSS rendering bugs have been fixed?
Numerous CSS rendering issues have been addressed. Flex layout now uses the used flex-basis value for definiteness evaluation instead of the specified one, which resolves sizing inconsistencies. Element positioning has been corrected when the containing block is an anonymous block. The box-shadow property now works on display: table-row elements. text-indent with calc() containing percentages correctly treats percentage components as zero for intrinsic size contributions. Out-of-flow content with fit-content height now calculates correctly. Other fixes include percentage size resolution in flex items under quirks mode, clip-path: inset() with border-radius rendering at various sizes, sizing inside <fieldset> for -webkit-box emulation, and proper layout for display: table elements with borders. Additionally, elements with border, position: absolute, and aspect-ratio: 1 now render as squares.
Were there any performance improvements for selectors?
Yes, a performance improvement specifically targets pages that use :where and :is pseudo-class selectors. These modern CSS selectors can sometimes be computationally expensive, especially when used in large quantities or with complex arguments. The WebKit team optimized the matching engine, resulting in faster rendering and reduced style recalculation times for sites relying on these selectors. This improvement is part of the broader CSS fixes in this release, but it deserves special mention because it directly impacts page load and interaction performance.
What’s the WebKit change range for this release?
Safari Technology Preview 243 includes all WebKit changes from revision 310600@main up to 312007@main. This range covers the full set of code modifications, bug fixes, and feature additions between those two checkpoints. Developers can browse the specific commits to see exactly what changed at the source level. For casual users, it’s enough to know that this update brings together a considerable number of improvements under the hood, from accessibility to CSS rendering.