The macOS 14 Sonoma betas and release candidate have a bug in the firewall that is causing issues for our app. Apple introduced this bug during the beta period and it prevents our app from working properly. It can also result in leaks when certain settings are enabled. We have reported the bug to Apple, but it is still present in later betas and the release candidate. We have tried to find a solution, but unfortunately, there doesn’t seem to be one. This bug affects more than just our app and we believe Apple needs to fix it. If the bug is still present when macOS 14 is released, we recommend remaining on macOS 13.
https://mullvad.net/en/blog/2023/9/13/bug-in-macos-14-sonoma-prevents-our-app-from-working/