Release Notes for Safari Technology Preview 115

Safari Technology Preview Release 115 is now available for download for macOS Big Sur and macOS Catalina. If you already have Safari Technology Preview installed, you can update in the Software Update pane of System Preferences on macOS.

This release covers WebKit revisions 267325-267959.

Web Inspector

  • Sources Tab
    • Added a checkbox to the popover when configuring a local override to allow it to skip the network (r267723)

Web Audio

  • Enabled the modern unprefixed WebAudio API (r267488, r267504)
  • Changed AnalyserNode to downmix input audio to mono (r267346)
  • Changed AnalyserNode’s getByteFrequencyData() and getFloatFrequencyData() to only do FFT analysis once per render quantum (r267349)
  • Changed AudioBufferSourceNode to update grain parameters when the buffer is set after rendering has started (r267386)
  • Updated AudioParam.setValueCurveAtTime() to have an implicit call to setValueAtTime() at the end (r267435)
  • Updated AudioParams with automations to process timelines (r267432)
  • Fixed BiquadFilterNode’s lowpass and highpass filters (r267444)
  • Fixed Web Audio API outputting silence for 302 redirected resource (r267507, r267532)
  • Made AudioBufferSourceNode loop fixes (r267443)
  • Changed to properly handle AudioParam.setTargetAtTime() followed by a ramp (r267381)
  • Improved AudioBufferSourceNode resampling (r267453)

  • Added stubs for AudioWorklet (r267744)

  • Added basic infrastructure for AudioWorklet (r267859)
  • Added stubs for AudioWorkletProcessor and AudioWorkletGlobalScope (r267891)


  • Fixed BigInt to work with Map and Set (r267373)
  • Enabled Intl.DateTimeFormat dayPeriod (r267454)
  • Updated Intl rounding behavior to align with specifications update (r267500)
  • Updated functions to consistently enumerate length property before name property (r267364)
  • Updated Array.prototype.sort to be consistent with specifications (r267514)
  • Implemented item method proposal, note that this will be renamed to at later (r267814)


  • Performance.navigation and Performance.timing are incorrectly exposed to workers (r267333)
  • Update User Timing interfaces to User Timing Level 3 (r267402)
  • Fixed visibilitychange:hidden event to fire during page navigations (r267614)
  • Re-aligned HTMLElement with the HTML spec (r267893)


  • Added support for HTMLMediaElement.setSinkId (r267472)
  • Fixed webkitfullscreenchange to fire for Shadow DOM elements (r267724)


  • Added support for the individual transform properties translate, rotate, scale, including accelerated animation (r267887, r267937, r267958)
  • Changed to clear the override width to properly compute percent margins in CSS Grid (r267503)

  • Implemented the CSS math-style property (r267578)

  • Implemented row-gap and column-gap for flex layout (r267829)
  • Implemented list-style-type: <string> (r267940)
  • Fixed CSS Selector an-plus-b serialization (r267812)
  • CSS serialization expects comments between certain tokens (r267766)
  • Fixed CSS variable causing a background url() to get resolved with a different base (r267951)
  • Updated to repaint as needed when adding and removing highlights (r267863)


  • Changed to not set the UV option if the authenticator doesn’t support it (r267369)

Selection API

  • Fixed selectAllChildren to return InvalidNodeTypeError when passed a DocumentType node (r267327)
  • Improved VisibleSelection, FrameSelection, and DOMSelection to preserve anchor and focus (r267329)


  • Updated toRTCIceProtocol to handle ssltcp candidates (r267401)


  • Added support for accessing the ‘SameSite’ cookie attribute (r267919)
  • Fixed several issues when switching to new browser context (r267918)