WebKit has posted Safari Technology Preview 255, and the announcement confirms the build for Mac on macOS Golden Gate and macOS Tahoe. What it doesn't name is individual features or fixes.
Confirm your macOS version first. If you're on one of those two releases, download from the official WebKit page and test the site or workflow that prompted the update.
In this guide, I have covered:
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What Safari Technology Preview 255 includes
You saw that Safari Technology Preview 255 is out and you want to know what changed. WebKit confirms the release and which Macs it runs on. It does not name individual features or fixes.
Release 255 is a preview build for Mac, not a standard Safari version. The official WebKit announcement lists macOS Golden Gate and macOS Tahoe as the systems it runs on.
The WebKit feed entry is dated October 22, 2026. That post is the record for this release.
The entry says nothing about a phased rollout or an automatic update path for this Technology Preview release.
Downloading Release 255 on your Mac
Before you download anything, confirm which macOS release your Mac is running. That check decides whether this build is even yours to install.
If you’re on macOS Golden Gate or macOS Tahoe, the preview was built for you. Then work through WebKit’s page in order:
- Open the linked WebKit release page.
- Download Safari Technology Preview 255 on a Mac running one of the two listed macOS versions.
The announcement confirms download availability and stops there. It doesn’t document the buttons on the page, the installation steps, or a way to check which build is running.
TIP: On any other macOS release, this preview isn’t the build you want. It targets Golden Gate and Tahoe only.
What to check once it’s installed
Start with whatever made you download the preview. Open the site or workflow that was misbehaving and test it the way you normally would. That gives you a usable answer, which the release post doesn’t.
If a page looked broken at phone width, viewing the mobile site layout in Safari on Mac is a faster check than dragging the window narrow.
If the page loads but serves stale content, clearing the DNS cache in Safari is the usual next step.
You’ll know the build is working when the thing that sent you looking for an update behaves the way you expect. If it doesn’t, keep an eye on the WebKit release page for follow-up detail.
Frequently Asked Questions
Which macOS versions support Safari Technology Preview 255?
WebKit lists macOS Golden Gate and macOS Tahoe. No other macOS versions appear in the release summary.
Where can I download Safari Technology Preview 255?
From the official WebKit release page linked above. That page confirms the preview is available for download.
What features or fixes are included in Release 255?
None are listed in the announcement. The official release page is the place to check for anything beyond the availability statement.
Is this a regular Safari update?
No. WebKit identifies the release as Safari Technology Preview Release 255, not a standard Safari version.
How can I check the installed Technology Preview version?
The announcement gives no version-check steps. Use the release page as your reference for anything beyond availability.
