Apple Releases iOS 18.6.1 with Restored Blood Oxygen Feature—Is It Worth the Update?

1. Improved Introduction

Apple has officially released iOS 18.6.1, a software update that might look small on paper but is making big waves among iPhone and Apple Watch users. Unlike flashy upgrades packed with dozens of features, this version focuses on a single, highly anticipated change: the return of the Blood Oxygen function that was previously disabled in the United States. While it may seem minor at first glance, this update highlights Apple’s ongoing battle to balance innovation, user health features, and legal challenges.

Tech communities, especially on Reddit, are buzzing with debates about whether iOS 18.6.1 is worth downloading immediately. Some users praise the workaround for restoring health insights, while others dismiss it as unnecessary if you’re outside the U.S. or don’t own a newer Apple Watch. So, is this update a must-have or just another incremental patch? Let’s dive in.

2. What’s New in iOS 18.6.1

2.1 Restored Blood Oxygen Experience

The standout feature in iOS 18.6.1 is the reintroduction of the Blood Oxygen feature for Apple Watch Series 9, Series 10, and Ultra 2 users in the U.S. As per Apple’s release notes:

“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.” 

Due to a prior patent dispute with Masimo, Apple had disabled this feature in the U.S., and now is re-enabling it via a workaround: while your Apple Watch still collects the raw data, the paired iPhone handles the calculation, and results appear only within the iPhone’s Health app, not on the watch face itself 

2.2 “Only” This Feature—No Other Listed Improvements

The iOS 18.6.1 update notes indicate this feature is the sole official change. There are no declared bug fixes or security patches in the release notes 

3. Security & Privacy

Apple hasn't highlighted any security updates or CVEs (Common Vulnerabilities and Exposures) in this release. Some Redditors noted as much:

“It doesn’t seem to have any new features, or even any security updates…” Reddit

Others mentioned that Apple's official statement includes “no published CVE entries,” which implies the update is narrowly focused on restoring the Blood Oxygen feature - Reddit.

4. Supported Devices

• iPhones running iOS 18.6.1 and paired with:

• Apple Watch Series 9, Series 10, or Ultra 2, but only if located in the United States.

Apple explicitly states that watches purchased outside the U.S., or those that originally included Blood Oxygen functionality, are unaffected by this rollout

So, in summary:

• Supported: U.S. Apple Watch Series 9, 10, Ultra 2 + iPhone with iOS 18.6.1

• Not impacted: International users, older Apple Watch models, or devices with the original Blood Oxygen enabled.

5. How to Update to iOS 18.6.1

Simple and streamlined:

1. On your iPhone, open Settings > General > Software Update.

2. Tap Download and Install for iOS 18.6.1.

3. After updating, open either the ECG app on Apple Watch or the Health app on iPhone to trigger the over-the-air download for the new Blood Oxygen feature. The process may take up to 24 hours. 

If you're updating the watch later via your iPhone:

1. In the Watch app, go to General > Software Update.

2. Tap Install and follow on-screen directions. - AppleInsider

6. Early Impressions & Reddit Reactions

Community feedback can be a goldmine of real-world insight—from minor improvements to quirks:

• Recognition of the workaround:

  “It’s mainly the AW blood oxygen hack for the poor folks in the USofA…” Reddit

• Cooler temperatures reported:

  “I’ve noticed my iPhone is significantly cooler to the touch… My 15 Pro has definitely seemed cooler…” Reddit
  Some users speculate improved thermal management, although this may be anecdotal.

• Mixed impressions on indexing and battery:

  “I updated to 18.6.1 and I don’t see indexing in the battery settings… probably not much to index.” 
  “Now much more battery drain.”

• Discussions about regional relevance:

  “So a useless update if I’m not from the US…”

• Uncertainty about whether to update or wait:

  “Should I update or wait some days… nothing noticeably changed.”

• Functionality concerns after installing:

  “The Blood Oxygen app is no longer available… check the Health app…”
  “You can’t take a reading on your watch… results available only in Health app under Respiratory section.”

   

Summary of Reddit Feedback:

7. Conclusion — Should You Update to iOS 18.6.1?

For U.S. Apple Watch Series 9/10/Ultra 2 Users:

Yes. If you rely on or want access to the Blood Oxygen feature, updating to iOS 18.6.1 (and watchOS 11.6.1) is essential—even though it's a workaround. It restores partial functionality and is better than no feature at all.

For Users Outside the U.S. or on Older Devices:

The update offers minimal benefit. Since there are no documented security or bug fixes, and the Blood Oxygen feature wasn’t disabled in your region, it's reasonable to wait—for now.

Considerations Before Upgrading:

• Expect the Blood Oxygen results to appear only in the Health app—not on the watch.

• Community experiences vary: some report better thermal performance, others see no change or even battery strain.

• Updates may bring minor background changes (like indexing not appearing in battery settings), but nothing major has been confirmed.

Final Thoughts

iOS 18.6.1 may not be a headline-grabbing update, but it's a lifeline for U.S. users awaiting the return of the Blood Oxygen feature on the Apple Watch. The workaround keeps health tracking alive, albeit in a less direct way.

If you're impacted, it's worth installing—if only to reclaim that functionality. Others may safely hold off until Apple introduces broader enhancements or security updates.