With watchOS 26, Apple is changing the way newer Apple Watch models work technically. It's not about new watch faces or fitness features, but about the underlying architecture—the foundation on which the entire system runs. For you as a user, this primarily means better performance, more options for apps, and a clearer focus on the future.
Apple has made a major change with watchOS 26. The current version introduces a new system architecture for certain Apple Watch models: Instead of the previous hybrid solution with arm64_32, the full arm64 architecture is now used. This affects the Apple Watch Series 9, Series 10, and the Apple Watch Ultra 2. The change was presented in the developer video "What's New in watchOS 26" and represents an important step in the technical development of the smartwatch.
What does the switch from arm64_32 to arm64 mean?
The Apple Watch has previously operated on a special architecture: arm64_32. This is a modified version of the standard 64-bit architecture that uses 32-bit pointers. This solution made sense because smartwatches have limited memory. The hybrid architecture could utilize modern 64-bit instruction sets while keeping memory requirements low. This is now changing with watchOS 26. The latest models—Series 9, Series 10, and Ultra 2—now use the standard arch64 architecture, as seen on iPhones and Macs. This architecture uses true 64-bit pointers, opening up new technical possibilities.
What are the specific advantages of arm64?
The switch to arm64 brings some noticeable technical improvements:
- Access to larger storage areas
- Better performance through more available registers
- More system resources for complex or compute-intensive apps
- Simplified development because tools and runtime environments are closer to other Apple platforms
- Better future-proofing, as Apple has already switched all other platforms to arm64
For you, this means that apps will be able to do more in the future, run more smoothly, and use functions that were previously not possible.
What happens to older Apple Watch models?
The Apple Watch SE (2nd generation) and Series 8 will continue to use the existing arm64_32 architecture. To ensure all apps continue to work on all devices, developers will need to deploy their applications for both architectures—arm64 and arm64_32. Xcode handles this process automatically, as long as the appropriate targets and architectures are entered in the project settings.
Do old apps still run on the new watches?
Yes. If an app was originally built for arm64_32, it will also run on the new models with watchOS 26—but not with optimal performance. Apple uses a compatibility layer here. For the best performance, apps should therefore be recompiled for arm64. Apple has also indicated that support for arm64_32 may be phased out in the coming years as the older models are gradually phased out. All other Apple devices already use arm64 exclusively.
watchOS 26 puts the system on track
watchOS 26 doesn't bring a visible revolution, but it does bring a very important technical change. The switch to the full arm64 architecture makes the latest Apple Watches more powerful and better prepared for future software developments. If you're using a current model, you'll benefit directly from this change. For developers, the switch means a certain adjustment in the build process, but also more options for app development. (Image: Shutterstock / nestudio99)
