The seventh developer betas of iOS 26 and watchOS 26 include a redesigned Blood Oxygen feature on Apple Watch Series 9, Apple Watch Series 10,

Apple released a small build update to iOS 26 developer beta 6, which does not re-enable the blood oxygen sensor on Apple Watch in spite of the earlier iOS 18.6.1 update that did.

Macworld Early last year, Apple made the bold, court-mandated decision to remove the blood-oxygen feature from the Apple Watch Series 9 and Ultra 2 in the U.S. over a patent dispute with medical technology company Masimo.