Ing. Calogero Bono
Apple has released the first developer betas of iOS 27.3, iPadOS 27.3 and macOS 27.3, with major news for Safari. Vertical tabs arrive, along with a dark mode that adapts even to sites that don't support it, and new Siri AI actions on tabs and browsing history. According to MacRumors and 9to5Mac, the release for everyone is expected in December. It matters for anyone who browses every day, but also for anyone who manages websites.
A few terms before we get into the facts. Developer beta is the first test version, the one most exposed to bugs. Vertical tabs are browser tabs arranged in a side column instead of across the top. Adaptive Dark Mode is the dark mode Safari generates on pages that don't have a dark theme. Siri AI is Apple's assistant, which uses Apple Intelligence. Tag here means an instruction in a page's code that a developer can add.
How do Safari's vertical tabs work?
Tabs line up on the left side of the window, in place of the horizontal bar. According to 9to5Mac, by default they appear as icons to save space, but you can widen the bar to read site titles.
The layout works with tab groups and with Topics, which appear when automatic ordering by Apple Intelligence is active in iOS 27, reports MacRumors. Pinning by dragging and quick switching between groups also keep working.
On iPhone you turn it on from Settings, Apps, Safari. On Mac and iPad also from the View menu.
What is Adaptive Dark Mode and what does it do to sites?
If you use dark mode and open a site with a light background, Safari shows a «Try» button. Tapping it, the browser creates a dark version of the page. According to MacRumors it darkens the background, changes text contrast, inverts logos and graphics, recolors vector elements and rebalances shadows.
Not every change applies to every site. You can enable the feature for all sites or site by site. If a page already has a native dark theme, the feature does not kick in.
Developers can add a tag that makes Safari ignore adaptive mode, so the site stays as they designed it.
What can Siri AI do inside Safari?
Siri can act on tabs and windows, that is sort them, move them, close them and organize them into groups. It can also clear history for a specific site and time period, for example the last 10 days, as MacRumors reports.
The most ambitious part is understanding the entire page, including inactive tabs and off-screen content. With several tabs open for a purchase, Siri could sort them by price. Apple says this feature is coming, but it is not in the first beta.
Devices compatible with Apple Intelligence are required. The topic ties into the work on language and markets described in Apple Intelligence in China with iOS 27.3.
When does iOS 27.3 arrive and what is in the beta?
The first beta is for developers from today. According to MacRumors the final version will come out in December after several testing cycles. We covered it in the first iOS 27.3 beta.
TechRadar also cites Audio Intelligence features for Apple Watch Series 12, such as Live rewind and Siri Recap, and the redesign of the Health app, which we covered in Apple Health redesigned in iOS 27.3 beta. For now, warns TechRadar, everything is only in developer betas, and it advises against installing them on everyday devices.
Limits to know
We don't know the exact release date, only that sources point to December. We have no independent tests on the quality of Adaptive Dark Mode, and the promise not to break sites comes from Apple. Siri's full understanding of pages is not in the first beta and could change. Siri features require hardware compatible with Apple Intelligence.
What changes for those who work digitally
If you run a site or an online shop, check how it looks with adaptive dark mode. Logos with white backgrounds, vector graphics and shadows could be transformed. If the result is unacceptable, you can implement your own dark theme or use the tag to exclude Safari. Product pages in an online store also need reviewing with this in mind. Vertical tabs, meanwhile, take up more vertical space, so test layouts in narrower windows.
Our take
Vertical tabs are not new – Arc by The Browser Company made them popular, and 9to5Mac notes that Arc stopped development last year and will shut down in December. It's a useful choice, but not a novelty. The interesting part is adaptive dark mode, because it moves a design decision from the site to the browser. For those who publish content it's a control risk, mitigated by the exclusion tag. On Siri we'll wait to see the real feature before judging.
Frequently asked questions
When does Safari with vertical tabs come out?
Sources point to December for the final version of iOS 27.3, iPadOS 27.3 and macOS 27.3. Today there is only the developer beta. Apple has not given a precise date.
How do you turn on vertical tabs?
From Settings, Apps, Safari on iPhone, or from the View menu on Mac and iPad. By default they show only icons, but you can widen the bar.
Does Adaptive Dark Mode work on every site?
No. It doesn't kick in on sites with a native dark theme or that are already dark. Each page is adapted based on what is needed to make it readable.
Can developers block it?
Yes. They can add a tag that makes Safari ignore adaptive mode, and the site appears as they designed it.
Do you need special devices for Siri in Safari?
Yes, you need a device compatible with Apple Intelligence. Full page understanding is not in the first beta.
What to watch in Safari betas until December
The next betas will show whether Apple's promises hold up. Three points are worth following.
- Watch when the Siri feature that reads the entire page arrives, absent from the first beta.
- Check whether upcoming independent tests show dark mode errors on real sites.
- See whether Apple changes the exclusion tag or the default settings before release.
