watchOS 27 Is Here — But Not for Everyone
Every year, Apple rolls out a new version of watchOS, and every year, a handful of older Apple Watch models get left behind. With watchOS 27, that tradition continues — but this time, the reasoning is more significant than ever. Five Apple Watch models will not receive the update, and the culprit is a familiar one: Apple Intelligence. As Siri AI and related Apple Intelligence features become increasingly central to the Apple Watch experience, older hardware simply cannot keep up. If you own one of the affected models, here is everything you need to know about what is happening, why it is happening, and what your options are.
Which Apple Watch Models Won't Get watchOS 27?
Apple has confirmed that the following five Apple Watch models will not be eligible for the watchOS 27 update:
- Apple Watch Series 4 — Released in 2018, this model introduced the dramatically redesigned form factor that defined the modern Apple Watch look, but its aging S4 chip is no longer capable of handling the demands of watchOS 27.
- Apple Watch Series 5 — Best known for introducing the always-on display, the Series 5 shares the same S5 chip limitations that prevent it from running the latest software.
- Apple Watch Series 6 — Despite being celebrated for its blood oxygen sensor at launch, the Series 6's S6 chip falls short of the processing threshold required for Apple Intelligence features.
- Apple Watch SE (1st generation) — Apple's budget-friendly option from 2020 lacks both the chip architecture and the RAM needed for the new AI-driven capabilities in watchOS 27.
- Apple Watch Series 7 — Even the Series 7, which brought a larger display and faster charging when it launched in 2021, has been cut from the watchOS 27 compatibility list due to hardware constraints tied to Apple Intelligence.
If your Apple Watch is a Series 8, Series 9, Apple Watch Ultra, Apple Watch Ultra 2, Apple Watch SE (2nd generation), or Apple Watch Series 10, you are in the clear and can expect to receive the watchOS 27 update when it rolls out later this year.
The Real Reason: Apple Intelligence and Siri AI
So why are these five models being cut at the same time? The answer comes down to Apple Intelligence, Apple's expanding suite of on-device AI features that the company first introduced in 2024. Apple Intelligence relies on powerful machine learning models that run locally on the device, which means the hardware doing the processing needs to meet a specific performance threshold. Older Apple Watch chips — the S4 through S7 — simply do not have the neural engine capabilities, the RAM, or the processing speed required to run these workloads efficiently.
Siri AI upgrades in watchOS 27 are particularly demanding. Apple has made Siri on watchOS significantly smarter, capable of handling more complex, contextual requests without needing to offload processing to an iPhone or a server. This on-device intelligence is one of the headline features of watchOS 27, but it requires the S9 chip or later to function. The S9 chip, introduced with Apple Watch Series 9 and the Apple Watch Ultra 2 in 2023, was the first Apple Watch chip to include a dedicated four-core Neural Engine capable of performing up to 60 billion operations per second. That is the baseline watchOS 27 demands.
What Does This Mean for Affected Apple Watch Owners?
If you own one of the five unsupported models, your watch will not simply stop working overnight. Apple Watch models that do not receive watchOS 27 will continue to run on their last supported version of watchOS, which means your existing apps, health tracking features, and notifications will keep functioning as normal. However, you will miss out on everything new that watchOS 27 brings to the table.
Over time, this creates a growing gap. App developers will begin optimizing their watchOS apps for watchOS 27 features, and some new applications may require the latest OS to install or run properly. Health features that rely on Apple Intelligence-enhanced data analysis will be unavailable. And of course, the new Siri AI capabilities — which promise to make interacting with your watch far more natural and useful — will be entirely off the table.
Should You Upgrade Your Apple Watch?
Whether you should upgrade depends heavily on how central your Apple Watch is to your daily routine. If you are using your watch primarily for fitness tracking, sleep monitoring, and receiving notifications, an older model will continue to serve those purposes adequately for some time. However, if you are invested in the Apple ecosystem and want to take advantage of everything Apple Intelligence has to offer, upgrading to a supported model makes a compelling case.
The Apple Watch Series 9 represents the minimum entry point for full watchOS 27 compatibility, and it can often be found at a reduced price now that newer models have launched. The Apple Watch SE (2nd generation) is another cost-effective option that sits within the compatible range. For those who want the absolute best hardware Apple produces for the wrist, the Apple Watch Ultra 2 remains a powerhouse device built to handle years of future software updates.
A Pattern That Will Only Continue
It is worth noting that this kind of compatibility cutoff is not unique to watchOS. Apple follows a similar pattern with iOS, iPadOS, and macOS, gradually phasing out older hardware as new software demands grow. What makes the watchOS 27 situation notable is the speed at which Apple Intelligence has accelerated this process. Features that might have taken several more years to reach a level of hardware intensity that excluded mid-range devices have arrived quickly, thanks to Apple's aggressive push into on-device AI.
For consumers, the takeaway is clear: the Apple Watch upgrade cycle is shortening, and hardware released before the S9 chip era is now in the final chapter of its supported life. Apple's commitment to privacy-first, on-device AI processing is admirable, but it comes with a cost for those holding on to older devices.
The Bottom Line on watchOS 27 Compatibility
watchOS 27 marks a meaningful turning point for the Apple Watch platform. The decision to drop support for Apple Watch Series 4 through Series 7, as well as the first-generation Apple Watch SE, is driven by the hardware requirements of Apple Intelligence and the new Siri AI capabilities that sit at the heart of this update. While affected users will not lose core functionality immediately, they will increasingly find themselves on the outside of the Apple ecosystem's most exciting developments. If your Apple Watch falls on the unsupported list, now is a smart time to start planning your next upgrade.