Apple has released the fourth beta of macOS 10.15 Catalina for testing purposes to the developers



The new version comes two weeks after Apple released the third developer beta and can be downloaded using the Software Update mechanism in System Preferences. Apple has also warned of an incompatibility with Xcode 11 Beta 3 and SwiftUI previews.

General
New Features
Installing third party kernel extensions now requires that you restart your Mac before they’re permitted to load. (50340461)

Known Issues
macOS Catalina beta 4 does not support the MacBook Air model released in Summer 2019. A future beta of Catalina will add support for MacBook Air (Retina, 13-inch, 2019).

Warning

Your Secure Token might be lost if FileVault is enabled on a non-APFS formatted volume while upgrading to macOS 10.15. You might be able to work around this by disabling FileVault before upgrading to macOS 10.15, then reenabling FileVault once the upgrade has completed. (51091312)

During installation of macOS 10.15 you might be prompted to enter your administrator password multiple times to allow installation to proceed. (51206649)

Resolved Issues
You can unlock a Mac that has Activation Lock enabled when you use Recovery Assistant to erase it when reinstalling macOS. (52017040)

You no longer see only third-party applications when you click the Applications shortcut in the Finder sidebar if you used Migration Assistant to migrate your data to a Mac running macOS Catalina beta. (51651200)

Apps consistently relaunch after installation or applying an update. (51228752)

Deprecations
macOS frameworks are now thinned for the x86-64 architecture. Apps that execute i386 code now fail with the EBADARCH error code. The remaining stub frameworks are nonfunctional and exist only for compatibility purposes. (51236070)

macOS 10.15 Catalina Beta 4 release notes
Developer Downloads