Apple has seeded the first developer beta of iOS 27.3 (build 24C5037i), and it is a bigger update than the version number suggests. The redesigned Health app is back after being pulled from the iOS 27.2 release, Siri AI can now carry out actions inside Apple’s apps, Safari gains vertical tabs, and StandBy features that debuted on the iPhone Duo are expanding to every compatible iPhone. Matching 27.3 betas for iPadOS, macOS, watchOS, tvOS and visionOS arrived alongside it.
Two things to know before the tour: this is a developer beta — a public beta is expected in the coming days, and Apple plans the public release in December. And as with any first beta, features can change or disappear before that release.
Key Takeaways
- The Health app redesign returns: a new Insights tab (Activity Rings, heart rate, sleep, vitals, with Apple Intelligence guidance) and a Longevity tab tracking seven health categories, feeding a new Health Age estimate.
- Siri AI gains cross-app actions — unsubscribe or undo send in Mail, close duplicate tabs and clear history in Safari, organise Files — plus new languages and an App Intents preview for third-party apps.
- Safari adds a vertical tabs sidebar and an Adaptive Dark Mode that darkens websites which lack one.
- StandBy upgrades expand from the iPhone Duo to all compatible iPhones (iPhone 11 and newer), and the Duo itself gains a sideways Reachability mode.
- Apple Fitness+ adds Gym Strength, which builds custom four-week strength plans.
The Health App Redesign Is Back
The headline change is the return of the redesigned Health app. Apple tested it during the iOS 27.2 betas, then removed it before that update’s public release — as TechInKey noted when iOS 27.2 shipped without it. In 27.3 beta 1 it is back with two new tabs:
- Insights surfaces recent data — Activity Rings, heart rate, sleep and vitals — with Apple Intelligence offering personalised guidance on top.
- Longevity looks at your health over time across seven categories: heart health, sleep, mental wellbeing, movement health, metabolic health, hearing and nutrition.
Those feed a new Health Age estimate, comparing your health metrics with your actual age using Apple Watch data and fitness assessments captured with the iPhone’s camera, with optional blood-work biomarkers. One requirement worth noting: the redesigned app needs an Apple Intelligence-capable iPhone, so older models that can run iOS 27.3 will not see it.
Siri AI Learns to Do Things
Siri AI takes a practical step in this beta: instead of only answering, it can act inside Apple’s own apps — Calendar, Files, Journal, Mail, Maps, Messages, Music, Notes, Photos, Reminders, Safari, Shortcuts, Weather and more. Concrete examples from the beta:
- Mail: unsubscribe from mailing lists, and undo a recently sent message.
- Safari: close duplicate tabs, save articles to your Reading List, sort and move tabs between Tab Groups, and clear history for a specific site over a set period.
- Files: organise content and delete files you have not touched in a long time.
Siri AI is also expanding to Traditional Chinese, Vietnamese, Turkish and Norwegian, and a new App Intents developer preview lets third-party apps plug into the same system. One advertised ability is not in this beta: Siri understanding the full content of web pages, including inactive tabs. Apple says that awareness is coming later. As usual, the Siri AI features require an Apple Intelligence-capable device.
Safari: Vertical Tabs and Adaptive Dark Mode
Safari gets two visible changes. Vertical Tabs move your tabs into a sidebar on the left — icons by default to save space, with an option to widen it and show page titles. The layout works with both Topics and Tab Groups, and it is available across iPhone, iPad and Mac.
Adaptive Dark Mode tackles the blinding white page that ignores your Dark Mode setting: Safari offers a “Try” option that renders a dark version of the site, darkening backgrounds, adjusting text contrast and recolouring graphics.
StandBy for Everyone, Reachability for the Duo
StandBy — the glanceable clock-and-widgets display shown while an iPhone charges in landscape — is spreading its wings. The new StandBy features introduced with the iPhone Duo are coming to every iPhone that supports iOS 27.3, back to the iPhone 11: updated Analog and Digital clock faces with more colour and complication options, a Photos face that can pull from Shared Albums, and new Calendar and Weather faces.
The Duo gets its own fix in return: Reachability, reworked for its extra-wide display. Instead of shifting the screen down, enabling it (Settings → Accessibility → Reachability) lets a short side swipe shift the whole screen left or right so your thumb can reach the far side one-handed.
The Smaller Stuff
- Apple Fitness+ — Gym Strength: a new workout type that generates a custom four-week strength plan from your goals, experience, schedule and available equipment.
- Apple Music — Selfie Sing and Control Center VPN switching also appear in the beta’s feature list.
- Apple Watch: paired with watchOS 27.3, the beta adds Live Rewind and Siri Recap on the watch.
- China: the beta also begins testing the first Apple Intelligence features in China — the subject of our earlier story; Siri AI is not part of that rollout.
Should You Install It?
If you are not a developer, the honest answer is wait. First betas are the roughest builds of the cycle, and this one rearranges two things you rely on daily — your health data presentation and your browser. A public beta is expected within days if you want a safer early look, and the finished update reaches everyone in December, with mid-December the most likely window. If you do install the developer beta, do it on a spare device, not your daily phone.
The Bottom Line
iOS 27.3 beta 1 is Apple’s “finish what we started” update: the Health redesign that missed 27.2, a Siri that finally does chores inside your apps, a more capable Safari, and Duo perks shared with every iPhone from the 11 up. Whether all of it survives to December’s release is the open question betas always carry — but on this evidence, 27.3 is shaping up to be the most substantial point release of the iOS 27 cycle.
Related Guides
- Apple Intelligence Is Coming to China With iOS 27.3
- iOS 27’s Apple Intelligence Storage Problem — and the Workaround
- WhatsApp Will Require iOS 15.5 From November 30
FAQs
When will iOS 27.3 be released to everyone?
Apple plans the public release in December 2026, with mid-December the most likely window. The developer beta 1 (build 24C5037i) was seeded on November 3, 2026, and a public beta is expected in the coming days.
What is new in iOS 27.3 beta 1?
The redesigned Health app returns with Insights and Longevity tabs and a Health Age estimate; Siri AI gains actions inside apps like Mail, Safari and Files; Safari adds vertical tabs and Adaptive Dark Mode; StandBy features expand to iPhone 11 and newer; the iPhone Duo gains Reachability; and Apple Fitness+ adds Gym Strength plans.
Can I install iOS 27.3 beta 1 now?
Only registered developers can install it today. A public beta is expected soon, but first betas can be unstable and features may change before release, so most people should wait — and never install an early beta on their main phone without a backup.
Which iPhones get the redesigned Health app and Siri AI actions?
Those features require an Apple Intelligence-capable iPhone, so some older models that can install iOS 27.3 will not see them. The expanded StandBy features, by contrast, reach every compatible model back to the iPhone 11.
