--- title: Xcode 16.4 Release Notes framework: xcode-release-notes role: article role_heading: Article path: xcode-release-notes/xcode-16_4-release-notes --- # Xcode 16.4 Release Notes Update your apps to use new features, and test your apps against API changes. ## Overview Overview Xcode 16.4 includes SDKs for iOS 18.5, iPadOS 18.5, tvOS 18.5, watchOS 11.5, macOS Sequoia 15.5, and visionOS 2.5. The Xcode 16.4 release supports on-device debugging in iOS 15 and later, tvOS 15 and later, watchOS 7 and later, and visionOS. Xcode 16.4 requires a Mac running macOS Sequoia 15.3 through macOS Tahoe 26.1. General Resolved Issues Fixed: Users may see excessive CPU utilization from diskimagesiod which reduces simulator performance, increasing boot time, process launch times, and test execution times. (146716769) (FB16818022) Apple Clang Compiler Resolved Issues Fixed: The base template for std::char_traits is restored after being removed in Xcode 16.3; it is still deprecated and is going to be removed in a future release. Restoring the base template allows code that attempts to instantiate char_traits with types that are not provided by the Standard (for example, std::basic_string and similar) to still compile, giving it more time to transition. (149025504) Device New Features The command devicectl diagnose now obtains a sysdiagnose from your Mac and all available devices by default. (104845318) Instruments Resolved Issues Fixed: Improved error handling for the Processor Trace Instrument when targeting binary not signed with get-task-allow entitlement. (139032322) Simulator Resolved Issues Fixed: NSURLSession was always timing out and failing in iOS 18.3 simulator runtimes. (147849952) (FB17006003) Source Editor Resolved Issues Fixed: Some C++ headers were experiencing crashes in syntax highlighting and Quick Help. (148020379) ## See Also ### Xcode 16 - [Xcode 16.3 Release Notes](xcode-release-notes/xcode-16_3-release-notes.md) - [Xcode 16.2 Release Notes](xcode-release-notes/xcode-16_2-release-notes.md) - [Xcode 16.1 Release Notes](xcode-release-notes/xcode-16_1-release-notes.md) - [Xcode 16 Release Notes](xcode-release-notes/xcode-16-release-notes.md)