Apple confirms that watchOS 27 is compatible with the Apple Watch Series 9, after the device was briefly and mistakenly omitted from the official watchOS 27 compatibility list on Apple’s website following WWDC 2026. The compatibility page initially showed a shorter set of supported models, which suggested that Series 9 support might have been dropped. After developers and users began testing watchOS 27 developer beta 1, Series 9 owners reported they could download and run the beta, and Apple told outlets that the Series 9 exclusion was an error. The website listing has been corrected.

Beyond the Series 9 situation, Apple’s watchOS 27 update introduces a broader software compatibility cut. Sources agree that watchOS 27 supports only newer models—specifically the Apple Watch SE 3, Series 9, Series 10, Series 11, Ultra 2, and Ultra 3—and does not support older devices including the original Apple Watch Ultra (Ultra 1) and Apple Watch SE 2. Apple also drops support for earlier Series models, making this update the largest single-year reduction in Apple Watch software support to date. The update also adds features such as a new Siri experience and workout-related improvements.