iOS 18.6.1 now available, here’s what’s new

Chance Miller | Aug 14 2025 - 10:06 am PT

As expected, Apple is rolling out iOS 18.6.1 to iPhone users today. This update, along with watchOS 11.6.1, introduces a “redesigned Blood Oxygen feature” for Apple Watch Series 10, Series 9, and Ultra 2 in the United States.

What’s new in iOS 18.6.1?

As we reported this morning, Apple is rolling out a new version of the Blood Oxygen feature for Apple Watch users in the United States. This comes over 18 months after Apple began selling the Apple Watch without the Blood Oxygen feature in America due to a patent dispute with health technology company Masimo.

The redesigned version of the Blood Oxygen feature is available for Apple Watch Series 9, Series 10, and Apple Watch Ultra 2 users in the U.S. who do not have the original Blood Oxygen feature.

Here’s how the redesigned version of the feature works after updating to iOS 18.6.1 and watchOS 11.6.1.

You can initiate a session in the Blood Oxygen app on your Apple Watch, and the sensors on your Apple Watch will then collect the required data. Your iPhone utilizes this data to compute your blood oxygen measurements. The results are saved in the Respiratory section of the Health app on your iPhone. However, you won’t be able to view the results directly on the Apple Watch itself.

Here are Apple’s release notes for iOS 18.6.1:

This update provides a new Blood Oxygen experience for users in the United States with Apple Watch Series 9 and Series 10, and Apple Watch Ultra 2. Measurements are calculated on iPhone and viewed in the Health app.

Apple also says that there is “no impact to Apple Watch units previously purchased that include the original Blood Oxygen feature, nor to Apple Watch units purchased outside of the U.S.”

You can update your iPhone to iOS 18.6.1 by going to the Settings app, choosing General, then choosing Software Update. There are no other changes in the update.

After you update to iOS 18.6.1 and watchOS 11.6.1, your Apple Watch will also download an over-the-air asset for the new Blood Oxygen feature. This could take up to 24 hours. To help initiate the download, you can open the ECG app on Apple Watch or the Health app on iPhone.