iOS 18.6.1 Released: What’s New for iPhone Users

Apple has rolled out iOS 18.6.1, a minor update for iPhone users, focusing on a single key feature: the return of Blood Oxygen monitoring for select Apple Watch models in the U.S. Released on August 14, 2025, with build number 22G90, this update addresses a specific issue stemming from a patent dispute, offering no additional features or security patches. This concise article details the update’s purpose, functionality, and implications, tailored for iPhone users seeking clarity on what’s new.

What’s New: Blood Oxygen Feature Restored

The primary change in iOS 18.6.1 is the reintroduction of a redesigned Blood Oxygen feature for U.S. users of Apple Watch Series 9, Series 10, and Ultra 2, paired with watchOS 11.6.1. Key details:

• Background: A 2024 patent dispute with Masimo forced Apple to disable Blood Oxygen monitoring on these models in the U.S. The new system works around this by processing data on the iPhone instead of the watch.
• How It Works: Users initiate a session via the Blood Oxygen app on their Apple Watch, which collects sensor data. The iPhone then calculates measurements, storing results in the Health app’s Respiratory section. Results are not viewable on the watch itself.
• Availability: Only applies to U.S. models purchased without the original feature; existing or international units are unaffected.
• Setup: After updating, an over-the-air asset download (up to 24 hours) is required, triggered by opening the ECG or Health app.

Other Details

• No Additional Changes: Apple confirmed no new features, bug fixes, or security patches in iOS 18.6.1, making it a targeted release.
• Update Process: Go to Settings > General > Software Update to install. Ensure a Wi-Fi connection and 50% battery.
• Compatibility: Supports iPhone Xs, Xr, and later, including all iPhone 16 models and SE (2nd/3rd gen).

Implications

• User Impact: Restores a valued health feature for affected U.S. users, though the iPhone-dependent process is less seamless than the original.
• Legal Context: The workaround navigates Masimo’s patent restrictions, avoiding direct on-watch processing, and follows a U.S. Customs ruling.
• Future Outlook: Apple’s focus is shifting to iOS 26, expected in September 2025, suggesting iOS 18.6.1 is a stopgap for specific users.

iOS 18.6.1 is a niche update, restoring Blood Oxygen monitoring for select U.S. Apple Watch users via an iPhone-based workaround. With no other changes, it’s essential only for those impacted by the patent dispute. Update if you own a Series 9, 10, or Ultra 2 purchased in the U.S. post-ban; otherwise, expect more significant features in iOS 26.