Overview

• Apple released iOS 18.6.1 and watchOS 11.6.1 on August 14 to restore a redesigned Blood Oxygen experience for U.S. users whose watches sold without the feature.
• The new design retains sensor data collection on the watch but performs measurement and calculation on the paired iPhone, with results displayed in the Health app’s Respiratory section.
• Only Apple Watch models sold in the U.S. without the original Blood Oxygen feature—identifiable by specific part numbers—will receive the workaround, while older and international devices remain unchanged.
• Apple credits a recent U.S. Customs ruling for clearing the software-based workaround and is still pursuing appeals in its broader patent dispute with Masimo.
• Users may need to download an additional over-the-air asset after installing the updates, and Apple notes this activation step can take up to 24 hours.