I can tell you one thing though, @laland: if you have a working version of DFX, and you wish to keep it instead of upgrading to the new version, then whatever you do, do not uninstall DFX, since all licence keys for the legacy versions have become invalid.
Another option though, would simply be to uninstall DFX and to install the new free version available at fxsound.com, which will probably allow you to connect through Bluetooth without issues.
There are some compatibility issues with this way of connecting devices. Here are a couple of the search results:
Perhaps the developer will be able to report something else. Alas, due to the stoppage of the development of the program, a compatibility update cannot be expected.
I’ve been using the new version with Bluetooth headphones for years or however long it’s been out. Are you guys changing the settings in the sound panel? It also needs to be on when you turn your computer on. Mine connect automatically every single time.