Apple Shifts watchOS to arm64 Architecture for Enhanced Performance

Apple is making a significant transition in the technical framework that powers watchOS applications. With the upcoming release of watchOS 26, Apple will adopt the arm64 architecture, moving away from the previous arm64_32 framework. This was announced during a developer video presented at the World Wide Developers Conference (WWDC) 2025.

As a result of this change, developers will be required to create two different binaries to ensure compatibility with all supported Apple Watch models. The official rollout of watchOS 26 is expected in the fall, likely in September, following a beta testing period for developers that commenced recently, with a public beta available in July.

The new arm64 architecture will be supported by the Apple Watch Series 9, Apple Watch Series 10, and Apple Watch Ultra 2. However, earlier models such as the original Apple Watch Ultra, Series 8, and second-generation SE will continue operating on the arm64_32 architecture. This distinction highlights the necessity for developers to provide a second binary to maintain functionality across all devices.

The arm64 architecture offers enhanced performance and allows for access to larger memory spaces, representing a complete 64-bit architecture aligned with standard ARM specifications. This upgrade holds the potential for more complex and resource-intensive watchOS applications, addressing the limitations of the previous arm64_32 system, which had combined 64-bit architecture with 32-bit pointers to accommodate the restricted memory capabilities of wearable devices.

While the Apple Watch Ultra, Series 8, and SE will remain on the arm64_32 framework, all existing applications designed for this architecture will continue to function on the new arm64 devices thanks to a compatibility layer implemented by Apple. Nevertheless, developers are encouraged to optimize their applications for arm64 or at least recompile them to fully leverage the improved capabilities of the new architecture. It is anticipated that the arm64_32 framework may eventually be phased out entirely, as arm64 is already the standard for iPhone, iPad, and Mac devices.

The introduction of the arm64 architecture raises questions about whether it will lead to a notable improvement in the performance of watchOS applications, particularly given current feedback indicating a lack of robustness in existing watch applications.