# Safari Technology Preview 11 Release Notes Preview the latest web technology updates including: JavaScript, Web APIs, ApplePay, Web Inspector, MathML, CSS, Rendering, Media, Accessibility, and Content Blockers. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 11 is now [available for download](https://webkit.org/downloads/) for both macOS Sierra betas and OS X El Capitan. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab. This release covers WebKit revisions [203771–204289](http://trac.webkit.org/log/?rev=204289&stop_rev=203771&limit=999). ### JavaScript - Updated behavior for a class that extends null to follow ECMAScript 2016 specifications ([r204058](https://trac.webkit.org/changeset/204058)) - Made the second argument for `Function.prototype.apply` allow null, undefined or array-like data ([r203790](https://trac.webkit.org/changeset/203790)) ### Web APIs - Add support for `DOMTokenList.replace()` ([r204161](https://trac.webkit.org/changeset/204161)) - Add support for `Element.getAttributeNames()` ([r203852](https://trac.webkit.org/changeset/203852)) - Made the first parameter mandatory for `canvas.getContext()` and `probablySupportsContext()` ([r203845](https://trac.webkit.org/changeset/203845)) - Made the first two parameters madatory for `window.postMessage()` ([r203846](https://trac.webkit.org/changeset/203846)) - Made the first parameter mandatory for `Document.execCommand()` and `queryCommand*()` ([r203784](https://trac.webkit.org/changeset/203784)) - Made the first parameter mandatory for `HTMLMediaElement.canPlayType()` ([r203806](https://trac.webkit.org/changeset/203806)) - Made the first parameter mandatory for indexed property getters ([r203788](https://trac.webkit.org/changeset/203788)) - Made the first parameter mandatory for `Range.createContextualFragment()` ([r203796](https://trac.webkit.org/changeset/203796)) - Made the first parameter mandatory for `setTimeout()` and `setInterval()` ([r203805](https://trac.webkit.org/changeset/203805)) - Made the first parameter mandatory for `SVGDocument.createEvent()` ([r203821](https://trac.webkit.org/changeset/203821)) - Made the parameter mandatory for a named property getter ([r203797](https://trac.webkit.org/changeset/203797)) - Made the parameter mandatory for `table.deleteRow()` and `body.deleteRow()` ([r203840](https://trac.webkit.org/changeset/203840)) - Made the parameter mandatory for `tr.deleteCell()` ([r203833](https://trac.webkit.org/changeset/203833)) - Made the parameters mandatory for `CanvasGradient.addColorStop()` ([r203820](https://trac.webkit.org/changeset/203820)) - Made the parameters mandatory for `DOMParser.parseFromString()` ([r203800](https://trac.webkit.org/changeset/203800)) - Made the parameters mandatory for `Event.initEvent()` ([r203848](https://trac.webkit.org/changeset/203848)) - Made the parameters mandatory for `insertAdjacentText()` and `insertAdjacentHTML()` ([r203803](https://trac.webkit.org/changeset/203803)) - Enabled strict type checking for nullable attribute setters for wrapper types ([r203949](https://trac.webkit.org/changeset/203949)) - Enabled strict type checking for operations’ nullable parameters for wrapper types ([r203941](https://trac.webkit.org/changeset/203941)) ### ApplePay - Stopped accepting the deprecated `requiredShippingAddressFields` and `requiredBillingAddressFields` properties ([r203789](https://trac.webkit.org/changeset/203789)) ### Web Inspector - Improved the appearance of the Timeline tab when editing the enabled timelines ([r204125](https://trac.webkit.org/changeset/204125)) - Changed the Jump to Line keyboard shortcut to Control-G (⌃G) ([r204099](https://trac.webkit.org/changeset/204099)) - Fixed the grid column resizing element positions ([r203991](https://trac.webkit.org/changeset/203991)) - Added waterfall view to the Network tab and Network Timeline ([r203843](https://trac.webkit.org/changeset/203843)) - Fixed positioning of popovers when the window resizes ([r204264](https://trac.webkit.org/changeset/204264)) - Fixed popover drawing ([r204136](https://trac.webkit.org/changeset/204136)) - Polished UI for the Edit Breakpoint, Open Quickly, and Goto Line dialogs ([r204152](https://trac.webkit.org/changeset/204152), [r204124](https://trac.webkit.org/changeset/204124)) - Update the Visual Styles Sidebar to use a one column layout when narrow ([r203807](https://trac.webkit.org/changeset/203807)) - Fixed the behavior of Home and End keys to match system behavior ([r203804](https://trac.webkit.org/changeset/203804)) ### MathML - Polished MathML parsing ([r204038](https://trac.webkit.org/changeset/204038), [r204037](https://trac.webkit.org/changeset/204037), [r203896](https://trac.webkit.org/changeset/203896)) ### CSS - Aligned the CSS `supports` rule with the specification ([r203782](https://trac.webkit.org/changeset/203782)) - Addressed incorrect results for the `color-gamut` media query ([r203903](https://trac.webkit.org/changeset/203903)) ### Rendering - Fixed performance issues with `` with the `truespeed` attribute ([r204197](https://trac.webkit.org/changeset/204197)) ### Media - Fixed captions not rendering in the PiP window for a hidden video element ([r203799](https://trac.webkit.org/changeset/203799)) - Addressed media controls not displaying for some autoplaying videos at certain browser dimensions ([r203928](https://trac.webkit.org/changeset/203928)) - Fixed media stream video element to show black when all video tracks disabled ([r203826](https://trac.webkit.org/changeset/203826)) ### Accessibility - Added localizable strings when inserting list types ([r203801](https://trac.webkit.org/changeset/203801)) - Improved the accessibility of media controls ([r203913](https://trac.webkit.org/changeset/203913)) ### Content Blockers - Enabled Content Blockers to block WebSocket connections ([r204127](https://trac.webkit.org/changeset/204127)) --- Copyright © 2026 Apple Inc. 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