Apple Releases Safari Technology Preview 248 – Brings Bug Fixes and Performance Improvements

Apple hasreleasedSafari Technology Preview 248, the latest version of its developer preview web browser. The preview version of Apple’s popular browser offers developers and other interested users the ability. . .

By @clhauk · July 23, 2026 · 8 min read

Apple hasreleasedSafari Technology Preview 248, the latest version of its developer preview web browser. The preview version of Apple’s popular browser offers developers and other interested users the ability to try out features that may or may not, debut in future public release versions of Safari. ‌Safari Technology Preview‌ 248 includes fixes and updates for Accessibility, CSS, Editing, Forms, Images, JavaScript, Media, Navigation, Networking, Rendering, SVG, Scrolling, Security, Storage, Web API, Web Inspector, WebDriver, and WebRTC. The current ‌Safari Technology Preview‌ release is compatible with machines running macOS 26 Tahoe and macOS 27 Golden Gate, the newest version of macOS that will launch later this year. The ‌update is available through the Software Update mechanism in System Preferences or System Settings to anyone who hasdownloaded the browserfrom Apple’s website. OverviewSafari Technology PreviewRelease 248 is nowavailable for downloadfor macOS Golden Gate and macOS Tahoe. If you already have Safari Technology Preview installed, you can update it in System Settings under General → Software Update. This release includes WebKit changes between:315567@main…316817@main. AccessibilityResolved IssuesFixed VoiceOver on Safari unable to navigate to content revealed by disclosure widgets usinghidden="until-found". (315964@main) (173228707)Fixed stalearia-labelledbywhen the referenced element dynamically changes itsaria-label. (316316@main) (180319221)CSSNew FeaturesAdded support for forwarding missing color components when interpolating between analogous color spaces. (315569@main) (180239320)Added support for theno-clampoption on the CSSprogress()function. (315977@main) (180473472)Resolved IssuesFixed serialization of various CSS at-rules not escaping identifiers. (315795@main) (178750383)Fixed:last-childand related selectors incorrectly gating on parser state outside of style resolution. (316495@main) (178879939)Fixed changing thecolor-schemeof annot invalidating the appearance of the embedded document. (316467@main) (179177141)Fixed CSS scroll snap re-snap to prefer the fragment-targeted (:target) snap area over other aligned snap targets. (315880@main) (180108825)Fixed the CSS preload scanner failing to preload@importrules that follow an@layerstatement rule. (315576@main) (180170656)Fixed serialization ofCSSViewTransitionRule. (315614@main) (180170814)FixedMediaList. deleteMedium()to parse its argument as a media query and remove all matching queries. (315579@main) (180270019)FixedMediaList. appendMedium()to parse its argument as a single media query and suppress duplicates. (315594@main) (180291283)Fixed grid items withstretchorfit-contentpreferred sizes computing incorrect minimum-content contributions when sizing tracks. (316296@main) (180748205)Fixed inserting a CSS rule while a view transition is active causing the group animation to snap to its final state. (316436@main) (181100818)Fixed CSSvar()to only resolve its fallback when the first argument resolves to the guaranteed-invalid value. (316280@main) (181114298)Fixed navigating away from a render-blocked document before its first rendering opportunity incorrectly firingpagerevealand starting an outbound cross-document view transition. (316446@main) (181191512)EditingResolved IssuesFixed drag images of DOM elements with CSS transforms not rendering correctly. (316077@main) (99614217)Fixed opaque DOM mutations coming from dictation on iOS. (316049@main) (163454428)Fixed deletion in an editable table leaving an empty trailing table row behind. (315990@main) (180877315)Fixed vertical caret movement in editable content ignoring the requested editable-type parameter. (316241@main) (181000174)FormsResolved IssuesFixed the concentric inner-button corner radius on horizontal text form controls incorrectly ignoring the bottom inset. (316022@main) (180869927)ImagesResolved IssuesFixed a regression where RGB gain map images were decoded to 8 bits per channel, causing a color shift and incorrect brightness. (316069@main) (179152566)Fixed handling of the gain-map target pixel format when decoding HDR images to fall back safely when the format cannot be parsed. (316405@main) (181180757)JavaScriptNew FeaturesAdded support for the TC39 BigInt Math proposal, exposingMath-equivalent methods onBigIntsuch asBigInt. powandBigInt. sqrt. (315974@main) (152472996)MediaResolved IssuesFixedandcontrols rendering incorrectly when rotated via CSS transform. (315718@main) (37516619)Fixed subtitles and closed captions not appearing in fullscreen video on iPhone. (315789@main) (175298523)Fixed ArrayBuffer-backed YUVVideoFramewith avisibleRectrendering with offset chroma channels. (315742@main) (180202939)Fixed video playback of streams from certain sources such as security cameras not working. (315774@main) (180411019)Fixed transient device rotation resulting in captured video frames having the wrong orientation. (315821@main) (180429147)Fixed Media Source Extensions playback and seek by loosening the gap tolerance between buffered ranges. (316146@main) (180439090)NavigationResolved IssuesFixed ato a URL differing only in fragment identifier being incorrectly treated as a page reload. (316001@main) (176933795)NetworkingResolved IssuesFixed URL path separators being encoded as%2Ffollowing a percent-encoded Armenian path segment. (315627@main) (180067095)RenderingResolved IssuesFixed the background of a compositedelement not being repainted when thebackground changed. (316415@main) (177975964)Fixed a regression where block-axis padding on aflexcolumn container withoverflow: autowas excluded fromscrollHeight. (315813@main) (179376053)Fixed an issue where anembedding an SVG with a near-integral intrinsic width rendered one device pixel narrower than expected. (315807@main) (180490343)Fixed elements withfilter: drop-shadow()not being fully repainted when a child is resized. (316450@main) (181284741)SVGResolved IssuesFixed SVG SMIL length animations to reject invalidto,from, andbyvalues such as those with leading whitespace. (315949@main) (118537155)Fixed Unicode text with complex scripts not rendering correctly along a curved. (316144@main) (120284006)FixedSVGLength. convertToSpecifiedUnits()failing when converting frompxto%,em, orex. (315953@main) (172056830)Fixed SVG geometry presentation attributes likecx,cy,r,rx,ry,x,y,width, andheightbeing incorrectly applied to elements such ason which they are not permitted. (315946@main) (175672111)Fixed an issue where the per-characterrotateattribute was discarded on a, so it now composes with the path tangent angle. (315786@main) (178044478)Fixed several SVG styling spec-compliance failures. (316174@main) (181052042)Fixed dynamic changes toorientandmarkerUnitsonnot repainting elements that reference it. (316350@main) (181106538)Fixed SVG SMILnumber,integer-optional-integer,number-optional-number, andpathanimations to not apply when theirfrom,to, orbyvalues fail to parse. (316468@main) (181308150)ScrollingResolved IssuesFixed CSS scroll snap points inside zero-sized elements not working correctly. (315948@main) (172863699)Fixed CSS scroll snap re-snap to prefer a snap area that contains the focused or fragment-targeted element. (315927@main) (180707984)SecurityResolved IssuesFixed a regression where some websites failed to display and logged Content Security Policy errors in the console. (316290@main) (179684592)Fixed same-page navigations being incorrectly checked against Content Security Policy. (315759@main) (180342503)Fixed Content Security Policyframe-ancestorsviolations in report-only policies being ignored instead of reported. (315753@main) (180447621)Fixed Content Security Policy parsing to reject trailing characters after the closing quote onnonce-sourceandhash-sourcevalues. (316008@main) (180903857)Fixed Content Security Policytrusted-typesexpressions to reject trailing characters after keywords and the wildcard. (316089@main) (180973793)StorageResolved IssuesFixed an issue where IndexedDB transactions could be blocked for an extended period before starting when another page’s transaction was suspended in the background. (315609@main) (178769599)Web APIResolved IssuesFixed the Async Clipboard API to request paste access asynchronously. (315997@main) (75969974)Fixed Digital Credentials to surfaceOperationErrorfor platform-cancellation and unknown errors instead ofAbortErrororUnknownError. (315973@main) (174308268)Fixed Digital Credentials rejecting with the wrong error code and synchronously; rejections are now queued as a task with the correct error. (315895@main) (174895437)FixedKeyboardEvent. getModifierState("AltGraph")andMouseEvent. getModifierState("AltGraph")always returningfalse. (315804@main) (180597374)FixedCredential. typereturning"digital-credential"instead of"digital"for digital credentials. (315891@main) (180618646)Fixed abortingnavigator. credentials. get()leaving the digital-credentials document picker stuck on screen. (316494@main) (180812397)FixedFileReader. readAsText()ignoring thecharsetparameter of theBlob’s MIME type. (315996@main) (180890703)Web InspectorResolved IssuesFixed showing ES2022 class private fields, methods, and accessors when inspecting object instances in the Console. (316171@main) (88527162)Fixed symbolic breakpoints in the debugger so they work with intrinsic functions. (315713@main) (99037335)Fixed a JavaScript breakpoint on a line containing only a semicolon not being triggered. (316519@main) (126707973)Fixed the Console REPL to allow redefinition of variables declared withletandconst. (316523@main) (143140659)Fixed the Timeline exporting and importing the wrong timestamp forperformance. mark()records. (316073@main) (145226764)Fixed local response overrides mapped to a file being interpreted as Latin-1 (ISO-8859-1) instead of their actual encoding. (316074@main) (149847746)Fixed the Media Logging setting not persisting across page loads. (315758@main) (154766890)Fixed symbolic breakpoints to work with native constructors such asArray,Date,EventTarget, andWorker. (316262@main) (157178256)Fixed missing stack traces for MIME type errors when importing modules. (316529@main) (169396940)Fixed the Accessibility sidebar being empty for nodes inside cross-origin iframes. (316399@main) (178562336)Fixed inline style invalidation to batchDOM. getAttributescommands per tick in cross-origin iframes instead of issuing one command per node. (316487@main) (178830496)Fixed DOM Storage read and write commands to resolve against the frame’s own origin in cross-origin iframes. (316501@main) (179249711)Fixed a moved breakpoint reverting to its original location after closing and reopening Web Inspector. (315585@main) (180083858)Fixed showing the formatted parameters string for prototype objects such asMap. prototype. (315599@main) (180298712)Fixed missing formatted parameter strings for object shorthand methods and arrow functions. (315723@main) (180466459)Fixed an unnecessary colon appearing in front of non-class function properties. (315731@main) (180476445)Fixed a self-canceling ternary that produced an incorrect cross-axis direction in the flex overlay. (316429@main) (181198803)Fixed the color picker force-converting picked colors to Display P3. (316419@main) (181201503)FixedPage. searchInResourcessilently omitting cache-backed resources from search results. (316421@main) (181202027)Fixed duplicate invalid CSS declarations both incorrectly displaying as Active in the Styles sidebar. (316418@main) (181203080)Fixed adopted constructable stylesheets being misclassified as User Agent stylesheets in cross-origin iframes. (316433@main) (181204768)Fixed an unsigned underflow that caused the DOM agent to spuriously report power-efficient playback. (316443@main) (181205602)FixedNetwork. setExtraHTTPHeadersto replace previously set headers instead of accumulating them. (316444@main) (181282814)WebDriverNew FeaturesAdded WebDriver support for the Digital Credentials API, including commands to simulate wallet payloads, indefinite waits, and user rejection. (316435@main) (168941907)WebRTCResolved IssuesFixed the WebProcessAudioSessionto remain active while microphone capture is live. (316394@main) (180505014)Fixed theconfigurationchangeevent being dropped when a source-side change occurred while aMediaStreamTrackwas muted; the event is now deferred until unmute. (316301@main) (180728609)Apple’s aim with ‌Safari Technology Preview‌ is to gather feedback from developers and users on its browser development process. ‌Safari Technology Preview‌ can run side-by-side with the existing Safari browser and while it is designed for developers, it does not require a developer account to download and use. Next UpSecond Public Beta Versions of Apple’s iOS 27 and iPadOS 27 Are Now Available

Source: mactrast.com