watchOS 27, released September 14, removes the Digital Crown double-click app-switching feature for all Apple Watch models and reserves it exclusively for the new Live Rewind audio transcript feature on Series 12 and Ultra 4. Older model owners lose functionality without gaining the new feature, and Apple offers no option to customize the button assignment or disable Live Rewind.
Apple released a new Apple Watch Magnetic Fast Charger (model A3277) that delivers 10W of power, double the previous 5W limit, enabling faster charging for the new Series 12 and Ultra 4 models. The $29 charger can add 12 hours of battery life to the Series 12 or 18 hours to the Ultra 4 in just 15 minutes, but requires both the new watch hardware and new charger to achieve these speeds.
The Apple Watch Ultra 4 launches September 18 at $799, offering improved health sensing, more memory, and better battery life compared to the Ultra 3. For existing Ultra 3 owners, upgrading is generally not worthwhile unless recovery tracking or extended battery life are priorities; new buyers should prefer the Ultra 4 unless the Ultra 3 is significantly discounted.
watchOS 27 removes the double-click Digital Crown shortcut for app switching on older Apple Watch models to make room for Live Rewind, a new 15-second audio transcript feature exclusive to Series 12 and Ultra 4. Older watches now open a dynamic app grid with the same gesture, disappointing users who relied on the quick multitasking feature.
Apple Watch Series 12 and Ultra 4 introduce a new Readiness app that scores user fitness readiness on a 0-10 scale based on activity, vital signs, and sleep data. The app requires upgraded hardware with new optical and electrical sensors and is exclusive to these latest models.