Apple's latest Apple Watch software update is creating an awkward situation. watchOS 27 brings Siri AI to the wrist for the first time, but it also cuts off five models that are hardly ancient. Series 6, Series 7, Series 8, the second-generation SE, and the original Apple Watch Ultra no longer qualify for the update.
The confusing part? Apple hasn't really explained why.
The Official Line
When Apple confirmed the compatibility list, Apple Watch and Health Product Marketing Manager Cait Dooley told TechRadar that Siri AI and the new tap gesture "work best" with the performance of newer chips. She pointed to Apple Watch Series 9 and later, Apple Watch Ultra 2 and later, and Apple Watch SE 3 as the supported models.
That is the full public explanation Apple has offered.
On the technical side, there is a plausible hardware reason. Series 9 introduced the S9 chip with a 4-core Neural Engine that handles machine learning tasks up to twice as fast as the S8's 2-core Neural Engine. The newer chip also enabled on-device Siri processing for the first time. If Siri AI on watchOS 27 relies heavily on that Neural Engine, older watches simply may not have the headroom to run it.
The Problem With Apple's Argument
Here is where it gets harder to follow. Siri AI on Apple Watch is not running the way you might think. The feature requires a nearby Apple Intelligence-enabled iPhone to handle the actual AI processing. Your watch is not crunching large language models on its own. The iPhone does that work, then sends the result back to your wrist.
So the question becomes: if the heavy AI lifting is happening on the iPhone, why does the watch's Neural Engine matter so much that it cuts off hardware from 2020 through 2022?
Apple has not answered this. The company points to the chip gap and calls it a performance decision. That may be entirely true, but it is not a complete answer. The on-device processing that Siri AI does on the watch itself, even with the iPhone handling the bulk of the work, apparently needs more computing power than the S8 chip can provide. But Apple has not published the specific technical threshold that excludes these watches.
The iPhone Paradox
The inconsistency that has caught attention across the tech press: Apple is keeping iPhone 11 (from 2019) on the supported list for iOS 27. An iPhone that is seven years old this fall will run the latest Apple software. But an Apple Watch from 2022, the original Ultra that cost $799 at launch, is being left behind.
"The Ultra is only four years old and was quite a premium product," TechRadar noted. Apple has never cut Watch generations this aggressively before. watchOS 26, released in 2025, supported Series 6 and later, the second-gen SE and later, and all Ultra models. That was a far more generous cutoff line.
This is the biggest Apple Watch compatibility cull in the platform's history. Apple is dropping three full generations of devices in a single update, and the reason appears to be AI: specifically a feature that still leans heavily on a paired iPhone to function.
What You Actually Lose
If you own one of the affected watches, it is not becoming a brick. Apple says these watches will continue to receive security updates and remain pairable with iPhones running the latest iOS. You will still get notifications, track workouts, and use Apple Pay.
What you lose is everything in watchOS 27: Siri AI, the new tap gesture, and whatever other software features Apple introduces this cycle. The supported watch list effectively defines the ceiling for your device going forward. Apple is no longer promising feature updates for hardware it sold as recently as 2022.
The irony is real: people who bought the original Apple Watch Ultra as a premium, future-proof fitness device are now on the outside of the AI features, while their iPhone 14 or 15 sitting in a drawer nearby could have handled the processing load.
What Apple Has Not Said
Apple's official statement does not identify a specific technical barrier. It describes a performance philosophy: newer hardware enables a better experience. That is corporate-speak for "this is where we drew the line," not a technical specification.
Until Apple publishes more detail, the most honest answer to "will Siri AI work on my older Apple Watch?" is: probably not, and Apple is not going to tell you exactly why.
The public beta of watchOS 27 is expected in July, with the full release coming this fall. If you are on an unsupported watch and curious how the feature actually performs, that will be the time to see whether the exclusion feels justified, or whether it feels like Apple simply needed a line in the sand.
Sources: AppleInsider, The Verge (Tom Warren), TechRadar, Basic Tutorials, Windows News