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# Safari Technology Preview 53 Release Notes

Preview the latest web technology updates including: Service Workers, WebRTC, Loading, Rendering, Media, Accessibility, CSS, Web API, and Web Inspector.

## Overview

[Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 53 is now [available for download](https://webkit.org/downloads/) for macOS Sierra and macOS High Sierra. If you already have Safari Technology Preview installed, you can update from the Mac App Store’s Updates tab. This release covers WebKit revisions [229535-230029](https://trac.webkit.org/log?stop_rev=229535&rev=230029&limit=999).

This release of Safari Technology Preview has a known issue where the modal won’t appear for websites that prompt for camera or microphone access.

### Service Workers

- Changed to use one service worker process per security origin ([r229735](https://trac.webkit.org/changeset/229735/webkit/))
- Changed to use the same SWServer for all ephemeral sessions ([r229872](https://trac.webkit.org/changeset/229872/webkit/))
- Fixed promptly terminating service worker processes when they are no longer needed ([r229927](https://trac.webkit.org/changeset/229927/webkit/))
- Included the security origin in the service worker process name ([r229878](https://trac.webkit.org/changeset/229878/webkit/))

### WebRTC

- Added support for VCP encoder on macOS and iOS ([r229920](https://trac.webkit.org/changeset/229920/webkit/))
- Fixed the RTCPeerConnection constructor to throw an exception for bad configuration parameters ([r229645](https://trac.webkit.org/changeset/229645/webkit/))
- Fixed setting SenderTrack to `null` calling `removeTrack` with RTCRtpSender ([r229587](https://trac.webkit.org/changeset/229587/webkit/))

### Loading

- Fixed CSS mask images to be retrieved using potentially CORS-enabled fetch ([r230006](https://trac.webkit.org/changeset/230006/webkit/))
- Fixed loading the stylesheet when changing the `<link>` element `rel` attribute from `preload` to `stylesheet` ([r229585](https://trac.webkit.org/changeset/229585/webkit/))

### Rendering

- Fixed invalidating descendants for `:nth-child` and `:nth-of-type` pseudo classes only when needed ([r229537](https://trac.webkit.org/changeset/229537/webkit/))
- Fixed positioning for text with letter spacing ([r229867](https://trac.webkit.org/changeset/229867/webkit/))

### Media

- Added Fullscreen API as an Experimental Feature ([r229680](https://trac.webkit.org/changeset/229680/webkit/))
- Prevented SVG root from being skipped while marking percentage height descendants dirty ([r229849](https://trac.webkit.org/changeset/229849/webkit/))

### Accessibility

- Fixed table row count when `role="row"` is added to in DOM ([r229879](https://trac.webkit.org/changeset/229879/webkit/))

### CSS

- Fixed CSS Grid auto repeat tracks computation with definite min sizes ([r229897](https://trac.webkit.org/changeset/229897/webkit/))

### Web API

- Added a query and fragment exception to the History API’s unique origin restriction ([r229540](https://trac.webkit.org/changeset/229540/webkit/))

### Web Inspector

- Changed “Force Print Media Styles” to not persist across Web Inspector sessions ([r229686](https://trac.webkit.org/changeset/229686/webkit/))
- Changed to not show checkboxes for invalid properties in the Styles sidebar ([r229941](https://trac.webkit.org/changeset/229941/webkit/))
- Fixed the ability to add a new class by editing the class attribute in the DOM tree outline ([r229744](https://trac.webkit.org/changeset/229744/webkit/))
- Fixed an instance of the main WebGL canvas having no reported size in the Canvas Tab ([r229659](https://trac.webkit.org/changeset/229659/webkit/))
- Fixed a recording initiated by the user to properly show immediately on completion ([r229620](https://trac.webkit.org/changeset/229620/webkit/))
- Fixed session dividers not being added when Console tab is not visible ([r229785](https://trac.webkit.org/changeset/229785/webkit/))
- Fixed flashing when switching between nodes in the Styles sidebar ([r229922](https://trac.webkit.org/changeset/229922/webkit/))
- Fixed losing focus when editing a property while a page is being loaded ([r229787](https://trac.webkit.org/changeset/229787/webkit/))
- Prevented the Shift-Command-Left Arrow (⇧⌘←) and Shift-Command-Right Arrow (⇧⌘→) keys from switching tabs when focused on color picker text fields ([r230001](https://trac.webkit.org/changeset/230001/webkit/))
- Removed redundant tooltips ([r229543](https://trac.webkit.org/changeset/229543/webkit/))

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