In a significant development following a protracted patent dispute, Apple has begun reinstating the blood oxygen saturation (SpO2) feature on select Apple Watch models sold in the United States. This restoration comes after a brief period where the feature was disabled due to legal battles with medical technology company Masimo.

The controversy stemmed from allegations that Apple's SpO2 technology, used in Apple Watch Series 6 and later models, infringed on Masimo's patented pulse oximetry technology. The U.S. International Trade Commission (ITC) ruled in favor of Masimo, leading to an import ban on Apple Watches with the feature and, ultimately, the deactivation of the SpO2 functionality via software updates in the US market for the affected models: Apple Watch Series 9, Apple Watch Series 10 (if released under a different name but technologically similar to Series 9), and Apple Watch Ultra 2.

Now, Apple has found a way to bring the feature back to these models through a novel software implementation. With the release of iOS 18.6.1 and watchOS 11.6.1 (note: these version numbers are placeholders based on typical Apple update patterns and should be updated with the actual versions), Apple has shifted the processing of blood oxygen data.

Under the new system, the Apple Watch continues to use its sensors to collect raw blood oxygen data. However, instead of performing the patented calculations and analysis directly on the watch, this raw data is now transmitted to the paired iPhone for processing within the Health app. The analyzed results are then displayed exclusively within the iPhone's Health application, no longer appearing directly on the Apple Watch itself.

This workaround was reportedly reviewed and approved by U.S. Customs and Border Protection (CBP), which determined that the new data processing pathway, with the critical calculations now occurring on the iPhone, falls outside the scope of Masimo's infringed patents.

This situation highlights the complexities of patent law in the technology sector and Apple's ability to innovate and adapt in the face of legal challenges. While the legal battle with Masimo is not entirely over, this software-based solution allows Apple to once again offer a key health monitoring feature to its US customers on the affected Apple Watch models. Users in the United States with Apple Watch Series 9 and Apple Watch Ultra 2 should look for these software updates to regain access to the blood oxygen feature, albeit with a slightly different user experience where results are primarily viewed on their iPhone.