Get Your Apps Ready for Apple’s New Watch Processor Architecture

Chris Hamons

Last fall, Apple announced that new applications and updates would need to support the Apple Watch Series 4.

“Starting March 2019, all new apps and app updates for iPhone, including universal apps, will need to be built with the iOS 12 SDK and support iPhone XS Max. All new apps and app updates for Apple Watch will need to be built with the watchOS 5 SDK and support Apple Watch Series 4.”

Apple Watch Series 4

The Series 4 watch runs on a new processor architecture, ARM64_32, and the Xamarin team has been hard at work adding support.

Today, we have a preview ready for testing and app submission. It is based upon the Xamarin.iOS SDKs shipping with Visual Studio 2019 and Visual Studio for Mac 8.0, currently in preview.

Get Started!

To get started, install or upgrade to the latest preview of Visual Studio, and then install the appropriate preview of Xamarin.iOS:

  • Visual Studio 2019: Install the Visual Studio 2019 version 16.2 preview.
  • Visual Studio for Mac 8.1: Click Visual Studio for Mac > Check for Updates > Select the Preview channel > Install updates.

After installing the preview, one manual step is required to opt-in to the new support.

  • Right click on the watchOS extension project > Tools > Edit File (or open in a text editor)
  • Add “, ARM64_32” to the MtouchArch node for the Release|iPhone configuration.
  • This will look similar to: ARMv7k, ARM64_32

Release Configuration

Currently, ARM64_32 (and thus Apple Watch Series 4) builds are limited to the Release configuration. Make sure to confirm that you are using Release builds when deploying to the Apple Watch Series 4 as debug builds are not supported in this preview.

Give It A Try!

We encourage you to try it out this preview and we look forward to receiving your feedback. If you have feedback or run into any issues, please create an issue on GitHub so that our team can look into it.