Just days before Apple’s anticipated September 9 event, a leak in watchOS 27 and iOS 27 betas exposes four significant features expected in the Apple Watch Series 12 and Ultra 4.
What’s New in Series 12 & Ultra 4
First up, a new standalone “Readiness” app appears in code—separate from the current Vitals app. It’s positioned right after the Workout app on watchOS 27’s Home Screen by default. The iOS 27 companion app also handles it when auto-organizing apps on its Home Screen. All this suggests Apple is building a more thorough recovery or readiness tracking experience into its wearable lineup.
Second, strength workouts are getting much richer. Apple is reportedly expanding internal health metrics to include sets, repetition counts, weights, equipment used, body side, and duration—giving users substantially more detailed tracking during strength training.
Third, improvements are coming to the optical sensors via a new sensor suite dubbed “Sunstone4p0.” This system aims to reduce signal noise and optimizes measurements based on wrist placement and orientation. The upgrade suggests better heart-rate readings—even when the reflected pulse signal is weak.
Fourth, storage capacity will likely increase. Code entries tied to the upcoming T8320 chip show signs that the Series 12 and Ultra 4 could offer up to 128 GB of onboard storage—double what current models provide.
Context and Expectations Ahead of Launch
These leaks align with earlier predictions that Apple’s next wearable line would center on fitness and health feature enhancements, rather than redesigning the case shape or aesthetic. It has already been reported that major design changes aren’t expected for Series 12 or Ultra 4.
The “pdfu” account behind these discoveries has previously flagged numerous internal references—from game controllers in macOS to surround sound modes in HomePod firmware—indicating a track record of accurate code-level findings.
With just a few days until Apple’s big unveiling, these four features suggest a focused upgrade path: better health tracking, more storage, and enhanced sensors. Users investing in Series 12 or Ultra 4 are likely to see real refinement in performance and utility, rather than flashy redesigns.
The bottom line: Apple seems to be sharpening its focus for wearables—strength workouts, health sensors, and storage—not reinventing them. Keep an eye on September 9 to see whether all four make the cut, and how Apple positions each in features vs. pricing. These could be among the biggest performance boosts in recent years.
