Apple seeded watchOS 27 developer beta 4, continuing the rollout toward the fall public release. The update arrives alongside beta 4 for iOS 27, iPadOS 27, and macOS Golden Gate, and is available through the Settings app on compatible Apple Watch models.
With nearly two months remaining before public launch, beta 4 is a refinement phase with no major new features. The flagship feature, Siri AI, landed in beta 3 and is still unreliable. Testers on Apple Watch Ultra 2 and Ultra 3 report that “device knowledge” requests, setting timers, opening apps, controlling HomeKit devices, fail consistently. Apple is working on fixes and reliability should improve over the next few betas. Siri AI in English arrives later this year, with other languages following.
What watchOS 27 actually changes
For anyone new to the betas, here’s what’s shipping this fall:
- Siri AI, A generative AI overhaul of Siri accessible from the wrist, paired with an iPhone running iOS 27. Siri answers broader questions, pulls context from personal data (like finding a door code from an email), takes actions inside apps, and adjusts Activity goals. A dedicated Siri app syncs conversation history privately via iCloud.
- Dynamic app grid, Pressing the Digital Crown opens a redesigned grid with the Siri app at center and recently used or popular apps arranged around it.
- One-handed tap gesture, Pinching index finger and thumb together once selects a widget in the Smart Stack, no wrist rotation or screen tap needed.
- Smarter Smart Stack, The stack is now more proactive, surfacing relevant widgets based on context.
- Workout Buddy offline support, Workout Buddy now runs on Apple Watch without a nearby iPhone, adds progressive metrics (distance, pace, duration increases), and supports Spanish.
- Cycle Tracking updates, New perimenopause and menopause support for tracking related symptoms.
- Treadmill accuracy, New machine learning algorithms improve treadmill readings.
- Consolidated Find My app, Find Devices, Find Items, and Find People merge into a single map-centric app, with Precision Finding for a paired iPhone, AirPods Pro 3, or AirTag 2.
Compatible models
watchOS 27 requires Apple Watch Series 9 or later, Apple Watch Ultra 2 or later, or Apple Watch SE 3, paired with an iPhone running iOS 27. That cuts off Series 6, 7, and 8, the original Ultra, and SE 2, a three-generation drop that Apple attributed to the processing demands of Siri AI and the new tap gesture.
A note on beta testing on Apple Watch
If you’re considering this beta, remember that Apple Watch cannot be easily restored to an earlier watchOS version if problems occur. Unlike an iPhone, there’s no simple path back, you wait for Apple to push a newer build that fixes the issue. Given that Siri AI device knowledge requests are still broken on Ultra models, that’s worth weighing before installing on a daily driver.
watchOS 27 public beta released on July 13, so non-developers can access this through the Apple Beta Software Program. Developer beta 4 is the more recent build either way.
