iOS 18.6.1 Restores Game-Changing Blood Oxygen Feature—But It Still Comes with New Hiccups

Apple has reintroduced a crucial health feature with the release of iOS 18.6.1, reinstating blood oxygen monitoring on the Apple Watch after nearly 18 months of restrictions in the United States. The return of this tool—once described as a potential lifesaver—comes as a relief to users, though the update has also triggered complaints of new glitches.

The blood oxygen feature, first disabled due to a heated patent dispute with medical technology company Masimo, is now available again on the Apple Watch Series 9, Series 10, and Ultra 2. However, instead of working directly on the watch, the readings now rely on an iPhone to process results, marking a significant change in how users access their health data.

Why the Feature Was Disabled

The dispute with Masimo over pulse oximetry patents forced Apple to pull the feature from US-sold Apple Watches in 2023. Reports confirmed that Apple was unable to sell models with the functionality enabled until US Customs approved a workaround.

With iOS 18.6.1 and watchOS 11.6.1, Apple has restored the tool worldwide. Now, the watch collects raw oxygen data and transfers it to the iPhone, where calculations are performed before results appear in the Health app's Respiratory section. This method avoids patent violations but also removes the option of viewing results instantly on the watch face.

With the official release of iOS 18.6.1, Apple has brought back a highly anticipated feature: blood oxygen monitoring on the Apple Watch Series 9, Series 10, and Apple Watch Ultra 2 for users in the United States.

This update marks a significant development, following a period of limitations due to ongoing legal disputes. However, although the new software reinstates this functionality, it also introduces new modifications, with some users now experiencing different problems.

The Key Changes in iOS 18.6.1

With the reintroduction of the Blood Oxygen tracking feature, the iOS 18.6.1 update is making waves online. A patent conflict with medical tech company Masimo had led to Apple turning off this functionality for American customers for nearly 18 months.

The feature had been disabled on Apple Watch Series 10 models sold in the United States. However, it has now returned, enabled by a new solution and a green light from US Customs—though it does not work exactly as it did before. Forbes reported that the software update will restore the feature to all compatible Apple Watches sold globally, provided both the new version and watchOS 11.6.1 are installed.

A New Method for Monitoring

The system now operates as a workaround: you still start the Blood Oxygen app on your Apple Watch, but the data is then sent to your iPhone for calculations and analysis, with the final result available in the Health app's Respiratory section.

Compatible Devices

• Apple Watch Series 9
• Apple Watch Series 10
• Apple Watch Ultra 2

The feature is no longer a native function of the watch itself—instead, it now requires both devices to work together.

The Reason for the Redesign

The new way the Blood Oxygen feature works is a direct result of the ongoing patent dispute with Masimo. By moving the calculation from the watch to the iPhone, Apple can avoid violating certain patents while still providing the health feature to its customers.

According to a Zeera report, Apple was forced to make a concession—but successfully found a way to restore the feature for its users.

The New Hiccups in iOS 18.6.1

Despite the triumphant return of this functionality, users are now reporting some new issues.

App crashes: A few users on Apple's discussion forums have mentioned that apps such as Messages and Settings are sometimes closing unexpectedly after the update.

Delayed syncing: Since the feature now relies on both the iPhone and Apple Watch, some users have noticed that results take longer to show up in the Health app.

Limited functionality: Unlike before, you cannot see your blood oxygen levels directly on the watch face or in separate watch apps. All the information is now located in the Health app on the iPhone.

Users are voicing their experiences with the new iOS update on X, where one user, LeakCore, issued a strong warning: 'Do NOT install iOS 18.6.1!' The user claims that the update has introduced significant issues, including problems with battery calibration, a disrupted SIM connection, and overall network instability.

In the comments section, user Leonard G tagged both @Apple and @AppleSupport to report, 'fox the battery issue not charging well, heating on the latest model, this is unthinkable.'

Compatibility and Installation

Apple's iOS 18.6.1 is designed to work with all iPhones released from 2018 onward. This includes the iPhone XS, iPhone XS Plus, and iPhone XR, along with every model that has come out since.

That list covers the iPhone 11, iPhone 12, and iPhone 13 series, and continues to the iPhone 16 series, as well as the second- and third-generation iPhone SE and the iPhone 16e.

All of these phones, except for the initial three —iPhone XS, iPhone XS Plus, and iPhone XR —will also be compatible with iOS 13.

To install the update, open the Settings app on your iPhone, select General, and then tap Software Update. From there, you will have the option to download and install the software. The software is a moderate download, weighing in at around 720MB, but the installation process should be pretty fast.

Apple's workaround has allowed the tech giant to side-step ongoing legal disputes and bring back a feature hailed by health experts as a valuable tool for spotting early signs of respiratory distress. However, the update highlights the delicate balance between innovation, intellectual property disputes, and user experience.

For now, iOS 18.6.1 restores a vital health tool to Apple Watch owners—but not without introducing new headaches that could leave some questioning whether the trade-off is worth it.