With Apple having now announced and made available for devlopers the next release of macOS (Sequoia), I wanted to put together a quick post (to be updated) on what I've found so far with macOS 15.0 beta and Xcode 16.0 beta.

• Automated tests were failing when I referenced TARGET_TEMP_DIR, because it looks like Xcode 16.0 doesn't always create it for running tests. I was able to resolve by ensuring the directory in my test code.

• There's a new version of the SPM Package.resolved file (version 3) that appears to only add one additional field (some kind of hash) and update the version. I'm not sure if it's incompatible with older versions of Xcode, so I've been reverting those two changes when I check in.

• When runing UI Tests with the new Xcode (esp. under macOS 15 and via automation) it appears that the XCUIApplication isn't always running and frontmost at the start. This causes problems with my code that checks window status.