Apple has detailed which of its smartwatch wearables will have access to watchOS 5, and the original Apple Watch is not among them.
The new platform, which adds a wide number of new features, will be available to the Apple Watch Series 1, Series 2, and Series 3 w/LTE wearables. WatchOS 5 will also require an iPhone running iOS 12 and up, which means an iPhone 5s or later.
WatchOS 5 adds improved notifications, third-party app access to Siri, podcasts, walkie-talkie, and automatic workout detection.
WatchOS 5 is in beta testing now and is expected to reach end users in the fall.