Apple expands watchOS 27.0.1 update to fix critical restart bugs

Apple has expanded the rollout of watchOS 27.0.1 to all compatible Apple Watch models, including the SE 3, Series 9, 10, 11, and Ultra 2 and 3. This emergency update follows an initial release for the Series 12 and Ultra 4 to address a critical bug causing unexpected system restarts. Technical reports suggest the crashes were linked to a Neural Engine timeout during intensive tasks like using Siri AI or editing watch faces.

Alongside the stability patch, Apple is rolling out broader software updates across its ecosystem, including iOS 27.0.1, iPadOS 27.0.1, and visionOS 27.0.1. The new watchOS 27 ecosystem introduces several features, such as a dynamic app grid that uses AI to suggest relevant applications, enhanced Siri integration, and a redesigned Health app that functions as an interactive wellness coach with guided assessments.

New hardware, specifically the Apple Watch Series 12 and Ultra 4, features redesigned health sensors that increase heart rate monitoring frequency to once every five seconds. This higher data density has led to reports of visible green light leakage from the sensors in dark environments, prompting the introduction of a Theater Mode to reduce measurement frequency to once every five minutes when activated.