Starting with the 6.5.1 version of Bria our System Requirements have changed.
Supported
11 - Big Sur
12 - Monterey
Support Dropped
10.14 - Mojave
10.15 - Catalina
If you are unable to update your OS, you may continue to use the 6.4.2 clients.
Note that we cannot offer full support for the older clients; these links are provided for convenience only.