Today Apple released the first Public Beta of macOS Catalina 10.15 (19A487m).
MacOS Catalina 10.15 (19A487m) Public Beta was released today on June 24th, 2019 at 12:00 CST. The first Public Beta was released just three short weeks after 10.15 Catalina was first announced at WWDC19. Even though this seems really early, the first public beta of macOS 10.14 Mojave was release just 2 days later on Jun. 26th 2018.
This Build Version (19A487m) looks to be the same as Beta 2 (19A487l).
You will not find this update in software update if you are running Beta 2 (19A487l). If you are running the current version you do not have to worry about updating or reinstalling with (19A487m).
macOS 10.15 Public Beta 1 Patch Notes
The patch notes for the first public beta release are the same as Beta 2 as noted above. If you would like to read them you can take a look at my previous post.
mrmacintosh.com/apple-releases-second-beta-of-macos-catalina-10-15-19a487l-beta-2/
The link below is Apple’s 10.15 Beta 2 release notes.
developer.apple.com/documentation/macos_release_notes/macos_catalina_10_15_beta_2_release_notes