Apple unveiled watchOS 27 this week, immediately flagging a compatibility cut. The update will no longer run on Series 6, Series 7, Series 8, the second‑generation SE, or the original Ultra. Only the third‑gen SE, Series 9, Series 10, Series 11, Ultra 2 and Ultra 3 remain eligible for the new software now for existing owners.

Product marketing manager Cait Dooley told Tech Radar the cuts aim to preserve performance. watchOS 27 introduces a Siri AI app, a dynamic app grid, and a tap gesture, all of which lean on the faster processors found in Series 9 and later, Ultra 2 and later, and SE 3, to ensure smooth operation on the hardware. Older watches can still pair with iPhones on the latest iOS and receive security patches.

Developers can test watchOS 27 in beta, with a public preview slated for July and a rollout this fall. Users forced off the update will continue receiving security updates, but miss out on AI‑driven features and UI refinements. Apple’s decision nudges owners toward newer hardware while keeping devices functional. The move also pressures resale markets, as older models lose software relevance, significantly lowering their value.