Apple said Thursday that it is updating its watches with a redesigned blood oxygen feature after a recent U.S. customs ruling. The software update will go out to the Apple Watch Series 9, Series 10 and Ultra 2 devices on Thursday.

Apple had to disable its original blood oxygen feature after the U.S. International Trade Commission issued a limited exclusion order in 2023, finding that Apple had violated some of Masimo’s patents. Masimo, which makes pulse oximeters and other patient monitoring devices, has been in an ongoing patent battle with Apple. 

In January 2024, Apple was able to use a software workaround to sell its Series 9 and Ultra 2 watches with a redesign that did not include a pulse oximeter function, BTIG analyst Marie Thibault wrote in a research note. The decision by the U.S. Customs and Border Protection, which had not been posted online as of Thursday, allowed Apple to add a different version of the feature back into its watches, the company said.

With the update, sensor data from Apple’s blood oxygen app will be measured, calculated and displayed in the paired iPhone app. Previously, the readings were displayed on the user’s watch. Apple said that there will be no change to previously purchased Apple Watches that have the original blood oxygen feature or devices sold outside of the U.S.

Masimo and Apple still have pending litigation. Apple has filed an appeal to the ITC’s import ban. Masimo also has a separate patent infringement case in California against Apple that is set to go to trial in November, Thibault wrote.  

Apple has also filed a patent case against Masimo. In an October 2024 verdict, a jury said Masimo must pay Apple $250, the statutory minimum, after finding a discontinued version of its smartwatches infringed on some, but not all, of Apple’s patents. Later that year, Apple was granted a motion for a new trial on whether Masimo infringed on two of the patents in question.