Apple today released iOS 18.6.1 for the iPhone and watchOS 11.6.1 for the Apple Watch Series 9, Apple Watch Series 10, and Apple Watch Ultra 2. The updates re-enable blood oxygen monitoring in the United States.
iOS 18.6.1 can be downloaded on eligible iPhones over-the-air by going to Settings > General > Software Update. watchOS 11.6.1 is available for newer Apple Watch models that have blood oxygen monitoring disabled, and it can be downloaded through the Apple Watch app on the iPhone.
Apple said that blood oxygen monitoring is coming back to U.S. Apple Watch models due to a "recent U.S. Customs ruling."
Back in early 2024, the United States International Trade Commission (ITC) found that Apple violated blood oxygen sensing patents owned by Masimo. The ITC implemented a trade ban, and Apple had to stop selling the Apple Watch Series 9 and Apple Watch Ultra 2. Sales resumed after Apple disabled the blood oxygen monitoring feature in Apple Watch devices sold in the U.S.
Since January 2024, no Apple Watch models purchased in the U.S. have had a functioning blood oxygen sensor, including the Apple Watch Series 9, the Apple Watch Series 10, and the Apple Watch Ultra 2.
With iOS 18.6.1 and watchOS 11.6.1, Apple is implementing a workaround. Data collected by the blood oxygen sensor on the Apple Watch will be processed on a paired iPhone, with the results available in the Respiratory section of the Health app.
The feature typically allows users to see a readout of their blood oxygen level right on the Apple Watch, but this isn't how it will work in the U.S.
The update is designed for Apple Watch Series 9, Apple Watch Series 10, and Apple Watch Ultra 2 models sold in the U.S. that do not already have blood oxygen sensing available. Blood oxygen monitoring remained available on older watch models, and there has also been no change to Apple Watch models sold outside of the United States.
