In a surprising press release, Apple announced that the dormant Blood Oxygen feature will be reenabled for Apple Watch Series 9, Series 10, and Ultra 2 users in the United States.

Background

The Blood Oxygen measurement feature was first introduced with the Apple Watch Series 6 in 2020 as a wellness tool to track SpO₂ levels. However, it was disabled on Apple Watches sold in the U.S. after January 18, 2024, due to patent-related litigation brought by medical technology company Masimo. The U.S. International Trade Commission found that Apple’s original implementation infringed on Masimo’s patents related to pulse oximetry, resulting in import restrictions and the removal of the feature from newer models sold in the U.S.

How the Feature Works Now

According to MacRumors, Apple says the feature has been redesigned to offload the actual processing of Blood Oxygen data to a connected iPhone rather than handling it directly on the watch. This change allows Apple to restore the functionality while avoiding the specific patent issue at the center of the dispute.

To use the feature, your Apple Watch must be running watchOS 11.6.1 and your iPhone must be updated to iOS 18.6.1.

Apple Watches still using the original implementation of the Blood Oxygen measurement are unaffected by these changes.

Link: Apple Newsroom