safaripreviewiconApple today released a new update for Safari Technology Preview, the experimental browser Apple first introduced in March of 2016. Apple designed the Safari Technology Preview to test features that may be introduced into future release versions of Safari.

Safari Technology Preview release 39a is a followup to Safari Technology Preview 39, which was released earlier this week but suffered from a crashing issue on launch on macOS High Sierra. The new update includes the same features with fixes and improvements for Beacon API, Directory Upload, Fetch API, Input Events, JavaScript, WebAssembly, WebRTC, Web Inspector, and Media.

With Safari 11 now available to developers through the macOS High Sierra beta, Apple is providing two versions of Safari Technology Preview, one for macOS Sierra users and one for those using macOS High Sierra.

The Safari Technology Preview update is available through the Software Update mechanism in the Mac App Store to anyone who has downloaded the browser. Full release notes for the update are available on the Safari Technology Preview website.

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 designed for developers, it does not require a developer account to download.

Top Rated Comments

redheeler Avatar
108 months ago
This is how they routinely deactivate software for their "obsolete" Macs to get you to go out and buy a new one.
As someone who owns a lot of older Macs from 2010 and 2011, now six or seven years old, I am actually surprised at how well they run Apple's latest software. It's true I upgraded them with SSDs, and newer versions of MacOS kind of need that to perform well - but it's certainly not the same as going out and buying a new Mac.

10 years ago, the newest Mac OS X running flawlessly on a 7-year-old Mac (or even older, as technically unsupported Macs from 2008/2009 can run MacOS Sierra today) was almost unheard of. The dual-processor G4 towers could just barely do ok on Leopard, and without official support from Apple (733 MHz+ was required).
Score: 6 Votes (Like | Disagree)
redheeler Avatar
108 months ago
The bigger question for me is what kind of quality control does "TimMAAY" have that no one even bothered to launch the build before releasing it to the public? I realize this is a beta release, but this is ridiculously embarrassing even for that. This is something that most Alpha releases don't even do!
Obviously the crash wasn't happening for everyone. I installed Release 39 on my 5K iMac, haven't updated to 39a, and no issues whatsoever.

I'm sure it was tested before release, and it didn't crash for them either - but it's simply not possible to take into account all possible issues and testing environments. I also wonder if somehow the app got corrupted during distribution, and some users downloaded the corrupted version while others did not. Only Apple knows for sure what happened.

But this is kind of the point of beta software, to find and fix issues that might be missed during Apple's own testing. Crash reports are sent and that helps Apple locate and fix an issue that otherwise may not be easy to discover or reproduce.
Score: 5 Votes (Like | Disagree)
kevinthebright Avatar
108 months ago
You're assuming that Apple wasn't testing to see how they could deliberately MAKE it crash on certain machines. Apple does this. This is how they routinely deactivate software for their "obsolete" Macs to get you to go out and buy a new one. I see this a lot on an older Mac Pro. Apple desperately wants the Silver Tower people to give up those machines but they won't because Apple doesn't have a product that does what they will do STILL after ALL these YEARS! :(
Do you have evidence or is this just a conspiracy theory?
Score: 3 Votes (Like | Disagree)
MacSince1985 Avatar
108 months ago
You're assuming that Apple wasn't testing to see how they could deliberately MAKE it crash on certain machines. Apple does this. This is how they routinely deactivate software for their "obsolete" Macs to get you to go out and buy a new one. I see this a lot on an older Mac Pro. Apple desperately wants the Silver Tower people to give up those machines but they won't because Apple doesn't have a product that does what they will do STILL after ALL these YEARS! :(
Can you give us some evidence or examples? I have one of those silver towers (2010, upgraded to 12-core 3.46GHz) and it runs everything I throw at it smoothly.
Score: 3 Votes (Like | Disagree)
JaguarF Avatar
108 months ago
479 points on html5test. Safari is catching up.
Score: 2 Votes (Like | Disagree)
mdriftmeyer Avatar
108 months ago
You're assuming that Apple wasn't testing to see how they could deliberately MAKE it crash on certain machines. Apple does this. This is how they routinely deactivate software for their "obsolete" Macs to get you to go out and buy a new one. I see this a lot on an older Mac Pro. Apple desperately wants the Silver Tower people to give up those machines but they won't because Apple doesn't have a product that does what they will do STILL after ALL these YEARS! :(
You have never worked for an OS company. Being NeXT/Apple alum nothing we did was overseen by Steven P. Jobs. To insinuate Timmmay isn't doing his job makes you look like an imbecile. I fully expect the child police of Macrumors to warn me for calling you out, but you are an imbecile.
Score: 2 Votes (Like | Disagree)

Popular Stories

Apple Wallet ID Illinois

Apple Plans to Expand iPhone Driver's Licenses to These 7 U.S. States

Wednesday December 24, 2025 8:40 am PST by
In select U.S. states, residents can add their driver's license or state ID to the Apple Wallet app on the iPhone and Apple Watch, and then use it to display proof of identity or age at select airports and businesses, and in select apps. The feature is currently available in 13 U.S. states and Puerto Rico, and it is expected to launch in at least seven more in the future. To set up the...
iPhone Top Left Hole Punch Face ID Feature Purple

iPhone 18 Pro Launching Next Year With These 12 New Features

Tuesday December 23, 2025 8:36 am PST by
While the iPhone 18 Pro and iPhone 18 Pro Max are not expected to launch for another nine months, there are already plenty of rumors about the devices. Below, we have recapped 12 features rumored for the iPhone 18 Pro models. The same overall design is expected, with 6.3-inch and 6.9-inch display sizes, and a "plateau" housing three rear cameras Under-screen Face ID Front camera in...
maxresdefault

Where's the New Apple TV?

Monday December 22, 2025 11:30 am PST by
Apple hasn't updated the Apple TV 4K since 2022, and 2025 was supposed to be the year that we got a refresh. There were rumors suggesting Apple would release the new Apple TV before the end of 2025, but it looks like that's not going to happen now. Subscribe to the MacRumors YouTube channel for more videos. Bloomberg's Mark Gurman said several times across 2024 and 2025 that Apple would...
maxresdefault

10 Mac Apps Worth Trying in 2026

Wednesday December 24, 2025 9:27 am PST by
2026 is almost upon us, and a new year is a good time to try out some new apps. We've rounded up 10 excellent Mac apps that are worth checking out. Subscribe to the MacRumors YouTube channel for more videos. Alt-Tab (Free) - Alt-Tab brings a Windows-style alt + tab thumbnail preview option to the Mac. You can see a full window preview of open apps and app windows. One Thing (Free) -...
iOS 26

iOS 26.2 Adds These 8 New Features to Your iPhone

Monday December 22, 2025 8:47 am PST by
Earlier this month, Apple released iOS 26.2, following more than a month of beta testing. It is a big update, with many new features and changes for iPhones. iOS 26.2 adds a Liquid Glass slider for the Lock Screen's clock, offline lyrics in Apple Music, and more. Below, we have highlighted a total of eight new features. Liquid Glass Slider on Lock Screen A new slider in the Lock...
airpods color prototypes

Apple Tested AirPods in Bright Colors

Saturday December 27, 2025 6:06 am PST by
Apple reportedly tested a version of the first-generation AirPods with bright, iPhone 5c-like colored charging cases. The images, shared by the Apple leaker and prototype collector known as "Kosutami," claim to show first-generation AirPods prototypes with pink and yellow exterior casings. The interior of the charging case and the earbuds themselves remain white. They seem close to some...
iPhone Fold Vertical Feature

Why Apple's Foldable iPhone May Be Smaller Than Expected

Tuesday December 23, 2025 5:21 am PST by
Apple's first foldable iPhone, rumored for release next year, may turn out to be smaller than most people imagine, if a recent report is anything to go by. According to The Information, the outer display on the book-style device will measure just 5.3 inches – that's smaller than the 5.4-inch screen on the ‌iPhone‌ mini, a line Apple discontinued in 2022 due to poor sales. The report has led ...
iPhone SE Cosmopolitan Clean

Apple Discontinued These 25 Products This Year

Wednesday December 24, 2025 7:24 am PST by
With the end of 2025 near, the time has come to look back at the devices and accessories that Apple discontinued throughout the year. Most of the products that were discontinued this year were simply replaced by a new model with an updated chip. However, the iPhone SE line was entirely discontinued when the iPhone 16e launched, and the iPhone Plus line is being phased out. Below, we have...
Foldable iPhone 2023 Feature Iridescent Search

Samsung Developing 'Wide Fold' With iPhone Fold-Like Design Ahead of Apple's 2026 Launch

Tuesday December 23, 2025 11:55 am PST by
Samsung is working on a new foldable smartphone that's wider and shorter than the models that it's released before, according to Korean news site ETNews. The "Wide Fold" will compete with Apple's iPhone Fold that's set to launch in September 2026. Samsung's existing Galaxy Z Fold7 display is 6.5 inches when closed, and 8 inches when open, with a 21:9 aspect ratio when folded and a 20:18...