The beta was notarized by Apple, but the Zip file that was uploaded was not. I don't know what Apple is objecting too, but if the current official release works in Sonoma the beta should too. I tested by downloading my self and in MacOS Vetura I get this message:
“GEDitCOM II” is an app downloaded from the Internet. Are you sure you want to open it?
I can click "Open" to open it. If that is what you got, just click open (it is safe). If you got something else or a new mesage, it could be a new so-called "feature" of MacOS Somoma. In the past, a work around has been:
1. Before starting the beta version, open System Preferences and go to Privacy and Security
2. Scroll down to bottom and make sure you have checked "App Store and Identified Developers." It is possible an "upgrade" to Sonoma changed to App store only (which Apple prefers because they get a nice cut of the gross sales).
3. Once that is set, start the application. In the past, when Apple block san app from opening, it provides a hidden a button in "Privacy & Security" to allowed you to run anyway. I have not try this in recent versions, however.
Let me know if these steps work. I will test in Sonoma myself, but again, if current posting works, the beta should too (once one works around Apple's efforts to stop you using your computer).
John Nairn