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# watchOS 9.1 Release Notes

Update your apps to use new features, and test your apps against API changes.

## Discussion

The watchOS 9.1 SDK provides support to develop watchOS apps for Apple Watch devices running watchOS 9.1. The SDK comes bundled with Xcode 14.1 RC, available from [Beta Software Downloads](https://developer.apple.com/download/). For information on the compatibility requirements for Xcode 14.1, see <doc://com.apple.documentation/documentation/Xcode-Release-Notes/xcode-14_1-release-notes>.

### Memory Allocation

#### Known Issues

- The system memory allocator `free` operation zeroes out most deallocated blocks in watchOS 9.1 beta or later. Invalid accesses to free memory might result in new crashes or corruption, including:
  - Read-after-free bugs that previously observed the old contents of a block may now observe zeroes instead
  - Write-after-free bugs may now cause subsequent calls to `calloc` to return non-zero memory

To debug these issues, use Address Sanitizer and Guard Malloc (see `libgmalloc(3)`). (97449075)

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