Masimo sues U.S. Customs and Border Protection in bid to block green light to enable blood oxygen monitoring on Apple Watches

When Apple released iOS 18.6.1 and watchOS 11.6.1 last week, bringing Blood Oxygen monitoring to previously excluded models following a U.S. Customs and Border Protection approval that allowed Apple to move forward with the “redesigned” experience on those devices, we had a gut feeling that patent troll Masimo wouldn’t let that go very far without a fight.

The new ruling effectively circumvented a previous ruling made by the International Trade Commission, which said that Apple couldn’t sell Apple Watches with a functional on-device Blood Monitoring feature, as the technology that Apple was using was found to infringe on pulse-oximetry patents held by medical technology company Masimo. If they didn’t comply, they wouldn’t be able to import the devices and sell them in the U.S.

Apple’s long-term solution was to keep the hardware on affected Apple Watches, but to use software to disable it. Up until just last week, owners of Apple Watches purchased after that ruling didn’t have a way to monitor their Blood Oxygen level, while Apple Watches sold before that ruling have enjoyed access to this feature even up until now.

And that’s exactly what the iOS 18.6.1 and watchOS 11.6.1 software updates were released for – to re-enable the hardware. On the other hand, the user experience has been “redesigned” from that on the original Apple Watches that sill have the feature, as monitoring occurs on the host iPhone rather than on the Apple Watch itself.

Somewhat expectedly, however, Masimo isn’t too happy that Apple found a way to keep using the supposedly ‘patent-infringed’ tech. Masimo has officially filed a lawsuit this week against U.S. Customs and Border Protection in an attempt to halt the aforementioned approval that Apple scored, which could have far-reaching consequences.

Litigation could take some time. If Masimo wins, then Apple could be forced to disable the feature on affected Apple Watches yet again; but if Apple wins, then Masimo may have to grin and bear the loss, effectively dealing with the U.S. Customs and Border Protection nod in Apple’s favor.

It will be interesting to see what happens next, as we’re sure many Apple Watch users have been waiting for the return of this feature, and attempts to take it away from them again is sure to anger those customers.