Apple Reintroduces Blood Oxygen on US Watches via iPhone Processing

Apple released iOS 18.6.1 for iPhone and watchOS 11.6.1 for the Apple Watch today, reintroducing a redesigned Blood Oxygen feature for U.S. users of the Apple Watch Series 9, Series 10, and Ultra 2. In a move tied to a long-running patent dispute, Apple shifted the blood-oxygen data processing from the watch to the paired iPhone, with results displayed in the Health app’s Respiratory section. The update is part of a broader push toward stable health features on the latest hardware, while keeping the rest of the user experience largely unchanged.

The rollout is targeted at U.S.-sold devices that previously did not have Blood Oxygen due to a patent dispute with Masimo. Watches outside the United States, and those that never lost the Blood Oxygen capability, are not affected. Users simply need to install iOS 18.6.1 on their iPhone and watchOS 11.6.1 on their Apple Watch to access the redesigned experience. The Blood Oxygen sensor on the watch still collects data, but processing and interpretation now occur on the iPhone, with the readout appearing in the Health app rather than directly on the watch face.

Apple’s wording characterizes the change as a practical workaround enabled by...