New Tools for 64-bit Support in Xcode 9.3 Beta

The newly released beta of Xcode 9.3 includes tools to help developers test 64-bit support in macOS High Sierra.

The last macOS release to support 32-bit apps without compromise is macOS High Sierra. Make sure future releases of your app are 64-bit compatible by using new diagnostic tools in Xcode 9.3 beta and testing on macOS 10.13.4 beta. This version of Xcode also builds 64-bit apps by default.

To install Xcode 9.3 beta you will need a Mac running macOS 10.13.2 or later. Xcode 9.3 beta includes SDKs for iOS 11.3, watchOS 4.3, macOS 10.13.4, and tvOS 11.3.


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Deprecation of macOS 32-bit support
To prepare for a future release of macOS in which 32-bit software will no longer run without compromise, starting in macOS High Sierra 10.13.4 a user is notified on the launch of an app that depends on 32-bit software. The alert appears only once per app.

Developers can use a new 64-bit testing mode in macOS 10.13.4 to test software for 64-bit compatibility. NOTE: It is strongly recommended that this mode is enabled only by developers or experienced IT administrators.

To enable 64-bit mode:
1. Launch Terminal
2. Execute the following command: sudo nvram boot-args="-no32exec"
3. Restart the machine

64-bit test mode prevents 32-bit processes from launching. Launching an app that depends on 32-bit software results in a notification that the application can’t be opened. Other types of software may fail silently, such as 32-bit versions of Dashboard and WebKit plugins, preference panes, and background processes.


Disable the test mode once the software is updated to work in 64-bit.
To disable the test mode:
1. Launch Terminal
2. Execute the following command: sudo nvram boot-args=“”
3. Restart the machine

In future beta releases, 64-bit test mode may provide additional information for the developer to
help test and qualify software.
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Developers can download Xcode 9.3 beta form the link below...

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