Apple just rolled out Safari Technology Preview 248. Don’t expect much in the way of new features here. It’s mostly a cleanup release, with fixes for CSS, JavaScript, video playback, and a bunch of other stuff under the hood.

Quick refresher if you’ve never touched it. Safari Technology Preview is the version Apple uses to test browser changes before they reach the Safari on your Mac. It runs alongside your regular Safari, and you don’t need a developer account to install it. This build runs on macOS Tahoe and the upcoming macOS Golden Gate.

Some of the fixes are worth calling out because you’d actually run into them. One stops subtitles and closed captions from vanishing when you watch a video fullscreen on iPhone. Another brings back video playback from certain sources like security cameras, which had just stopped working for some people. There’s also a fix for HDR photos that were showing up too bright and with an off-color.

Apart from this, developers also have something to look forward to. JavaScript now handles the TC39 BigInt Math proposal, so you get methods like ‎_‘BigInt.pow’_ and ‎_‘BigInt.sqrt’_ for working with really big numbers. CSS gets a new ‎’no-clamp’ option and does a better job blending colors between different color spaces.

The last build was a bigger deal. That was Safari Technology Preview 247, which added an MCP server so AI agents can poke around and test live web pages for you. This one isn’t trying to top that, and that’s fine by me.

Apple already made it clear it’s been putting most of its energy into stability this year. The team rewrote 20-year-old layout code and shipped more than 1,000 fixes since last fall, which we broke down in our look at everything coming in Safari 27.

If you’ve already got the browser, just head to Software Update in System Settings to grab it. Otherwise you can download it fresh from Apple’s site. The complete list of changes is on Apple’s developer pages if you want to dig through all of it.

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